Pidgin 2.10.4

* General:
- Support building against Farstream in addition to Farsight.
* IRC:
- Disable periodic WHO timer. IRC channel user lists will no longer automatically display away status, but libpurple will be much kinder to the network.
- Print unknown numerics to channel windows if we can associate them.
* MSN:
- Fix a possible crash when receiving messages with certain characters or character encodings.
* XMPP:
- Fix a possible crash when receiving a series of specially crafted file transfer requests.
* Windows-Specific Changes:
- Words added to spell check dictionaries are saved across restarts of Pidgin