Pidgin 2.7.7

# General:
- Allow multiple CA certificates to share the same Distinguished Name (DN). Partially fixes remaining MSN issues from #12906.
- The GNUTLS SSL plugin now discards any certificate (and all subsequent certificates) in a chain if it did not sign the previous certificate. Partially fixes remaining MSN issues from #12906.
- Open requests related to a file transfer are now closed when the request is cancelled locally.

# AIM and ICQ:
- AIM should now connect if "Use clientLogin" is turned off and the "Server" field is set to anything other than "login.oscar.aol.com" or "slogin.oscar.aol.com".
- Fix a crash on connection loss.