Condition variables instead of polling

Change sign message bitcoin address tooltip to "The address to sign the ...

Document strlcpy.h in assets-attribution.txt since it isn't MIT-licensed

Flush on log size instead of transaction count

removed obsolete boost workaround (boost ticket #4258)

Remove USE_SSL #define

Enable addmultisigaddress RPC call for main network

Remove half-implemented publish/subscribe system

Add ifdef RELEASE to makefile.osx as the compile-for-older-macs flags

Fix #955: Verify status of encrypt/decrypt calls to detect failed padding

small misc syntactic fixes

Keep a global counter for nOutbound, protected with its own waitable
critical section, and wait when all outbound slots are filled, rather
than polling.

This removes the (on average) 1 second delay between a lost connection
and a new connection attempt, and may speed up shutdowns.

This commit simplifies the locking system: CCriticalSection becomes a
simple typedef for boost::interprocess::interprocess_recursive_mutex,
and CCriticalBlock and CTryCriticalBlock are replaced by a templated
CMutexLock, which wraps boost::interprocess::scoped_lock.

By making the lock type a template parameter, some critical sections
can now be changed to non-recursive locks, which support waiting via
condition variables. These are implemented in CWaitableCriticalSection
and WAITABLE_CRITICAL_BLOCK.

CWaitableCriticalSection is a wrapper for a different Boost mutex,
which supports waiting/notification via condition variables. This
should enable us to remove much of the used polling code. Important
is that this mutex is not recursive, so functions that perform the
locking must not call eachother.

Because boost::interprocess::scoped_lock does not support assigning
and copying, I had to revert to the older CRITICAL_BLOCK macros that
use a nested for loop instead of a simple if.

Streamline UI ↔ Core interface

modified block DL progressbar to be more informative and precise

- rename wxMessageBox, remove redundant arguments to noui/qtui calls
- also, add flag to force blocking, modal dialog box for disk space warning etc
- clarify function naming
- no more special MessageBox needed from AppInit2, as window object is created before calling AppInit2

- Overall, this is better design
- This fixes problems with the address book UI not updating when the address book is changed through RPC
- Move Statusbar change detection responsibility to ClientModel

Code deduplication: make function in GUIUtil to get connection type to call object slot in GUI thread
with invokeMethod.

VC2010 compile fixes

Add Luke-Jr's PGP key to gitian-downloader