Correct debug.log output to show correct function the debug is coming from.

Define BOOST_SPIRIT_THREADSAFE at all json_spirit*.h inclusion sites

rather than at each include site.

Fixes #1371

Reopen log file on SIGHUP

Filter out whitespace and zero-width non-breaking spaces in address field validator

- Fixes issues with copy/pasting from web or html emails (#1325)

GUI: start rows in askpassphrasedialog.ui at 0 (not 1)

BDB: restore DB_PRIVATE flag to environment

Satoshi's commits fdbf76d4 and c8ad9b83 (SVN import) removed the
DB_PRIVATE flag from the environment.  In part, this enables processes
other than bitcoind to examine the active database environment.

However, this incurs a slight performance penalty versus working
entirely within application memory (DB_PRIVATE).  Because bitcointools
and other direct-BDB-accessing tools are not used by the vast
majority of users, prefer to default with DB_PRIVATE with the option
of disabling it if needed via -privdb=0.

Update Header Licenses

remove strncasecmp() + strnicmp() calls use boost::algorithm::istarts_with()

Finer-grained UI updates, move UI interface to boost::signals

- No longer invalidates selection model, thus retains selection on address book changes
- Fixes selection of new address when added

- Signals now go directly from the core to WalletModel/ClientModel.
  - WalletModel subscribes to signals on CWallet: Prepares for multi-wallet support, by no longer assuming an implicit global wallet.
- Gets rid of noui.cpp, the few lines that were left are merged into init.cpp
- Rename wxXXX message flags to MF_XXX, to make them UI indifferent.
- ThreadSafeMessageBox no longer returns the value `4` which was never used, converted to void.

Gets rid of `MainFrameRepaint` in favor of specific update functions that tell the UI exactly what changed.

This improves the efficiency of various handlers. Also fixes problems with mined transactions not showing up until restart.

The following notifications were added:

- `NotifyBlocksChanged`: Block chain changed
- `NotifyKeyStoreStatusChanged`: Wallet status (encrypted, locked) changed.
- `NotifyAddressBookChanged`: Address book entry changed.
- `NotifyTransactionChanged`: Wallet transaction added, removed or updated.
- `NotifyNumConnectionsChanged`: Number of connections changed.
- `NotifyAlertChanged`: New, updated or cancelled alert. As this finally makes it possible for the UI to know when a new alert arrived, it can be shown as OS notification.

These notifications could also be useful for RPC clients. However, currently, they are ignored in bitcoind (in noui.cpp).

Also brings back polling with timer for numBlocks in ClientModel. This value updates so frequently during initial download that the number of signals clogs the UI thread and causes heavy CPU usage. And after initial block download, the value changes so rarely that a delay of half a second until the UI updates is unnoticable.

translation updates / string updates

GUI: add an icon for Debug logfile -> Open in the RPC console

Get rid of snprintf (except one) with fixed buffers, shorten code

remove strncasecmp() + strnicmp() calls and replace that code via boost::algorithm::istarts_with() / do not call ipcInit() on Mac and Windows as this is unneeded currently

Default to DB_TXN_WRITE_NOSYNC for all transactional operations

Shared code for wallet lock help and check

make CheckDiskSpace() use 50 * 1024 * 1024 Bytes

change strings to Bitcoin (uppercase), where it is used as a noun and up...

Replace debug window icon with LGPL-licensed one (fixes #1348)

* This is safer than DB_TXN_NOSYNC, and does not appear to impact
  performance.
* Applying this to the dbenv is necessary to avoid many fdatasync(2)
  calls on db 5.x
* We carefully and thoroughly flush databases upon shutdown and
  other important events already.

The best log rotation method formerly available was to configure
logrotate with the copytruncate option.  As described in the logrotate
documentation, "there is a very small time slice between copying the
file and truncating it, so some logging data might be lost".

By sending SIGHUP to the server process, one can now reopen the debug
log file without losing any data.

Acquire an exclusive, advisory lock before sending output to debug.log
and release it when we're done. This should avoid output from multiple
threads being interspersed in the log file.

We can't use CRITICAL_SECTION machinery for this because the debug log
is written during startup and shutdown when that machinery is not
available.

(Thanks to Gavin for pointing out the CRITICAL_SECTION problems based
on his earlier work in this area)

change strings to Bitcoin (uppercase), where it is used as a noun and update strings to use "Qt" (and not qt or QT) / update initialisation of notificator to use qApp->applicationName() instead of a static string

JSON-RPC: remove 'getblocknumber' deprecated RPC

Create a maximum-10MB signature verification result cache.
This should almost double the number of transactions that
can be processed on a given CPU, because before this change
ECDSA signatures were verified when transactions were added
to the memory pool and then again when they appeared in
a block.

Loop over all inputs doing inexpensive validity checks first,
and then loop over them a second time doing expensive signature
checks. This helps prevent possible CPU exhaustion attacks
where an attacker tries to make a victim waste time checking
signatures for invalid transactions.