0.3.13 RC1 for Windows, please test

0.3.13 release candidate, to be released soon so please test:

- don't count or spend payments until they have 1 confirmation
- internal version number from 312 to 31300
- only accept transactions sent by IP address if -allowreceivebyip is specified
- dropped DB_PRIVATE Berkeley DB flag
- fix problem sending the last cent with sub-cent fractional change
- auto-detect whether to use 128-bit 4-way SSE2 on Linux
Gavin Andresen:
- option -rpcallowip= to accept json-rpc connections from another machine
- clean shutdown on SIGTERM on Linux