Bugfix: Instead of reporting "bitcoin-qt" for both bitcoind and Bitcoin-Qt, report "Satoshi" which is at least correct

As testnet has neither DNS seeds or built-in seed addresses to
bootstrap from.

Now the entire network upgraded to (initial) protocol version 209,
crtainl simplifications in the source code are possible.

Also report old and new best, and fork point.

Also moved RecvLine to net.cpp.

Fixes a memory leak.

When OpenSSL's BN_bn2mpi is passed a buffer of size 4, valgrind
reports reading/writing one byte past it. I am unable to find
evidence of this behaviour in BN_bn2mpi's source code, so it may
be a spurious warning. However, this change is harmless, as only
the bignum with value 0 results in an mpi serialization of size 4.

Fix #846.  Allow negative options such as "nolisten=1" in bitcoin.conf as well as on the command line.

Introduce an enum threadId, and use symbolic indices when accessing
vnThreadsRunning.

* do not let vnThreadsRunning[1] go negative
* do not perform locking operations while vnThreadsRunning[1] is decreased
* check vnThreadsRunning[1] at exit

needed for sending BIP16 transactions on test network through GUI

- icon from the LGPL Nuvola set (like the tick) - http://www.icon-king.com/projects/nuvola/
- include 'boost/version.hpp' in db.cpp so that the overwrite version of copy can be used
- catch exceptions in BackupWallet (e.g. filesystem_error thrown when trying to overwrite without the overwrite flag set)
- include db.h in walletmodel.cpp for BackupWallet function
- updated doc/assets-attribution.txt and contrib/debian/copyright with copyright info for new icon

* Fix sign error in calculation of seconds to sleep
* Do not mix GetTime() (seconds) and Sleep() (milliseconds)
* Do not sleep forever if walletlock() is called
* Do locking within critical section