[Azoth OTRoid] Fixed compat with libotr 4.

Fixed problem of initialization of private conversation when both sides use
libotr 4.0.x. Protocol OTRv2 is forced. This is temporary solution.
Merge branch 'master' into otroid-fixes
[Azoth OTRoid] Detect the end of private conversation.

Show user the message that interlocutor ended private conversation.
[Azoth OTRoid] Notify user about changes in OTR status.

Show user the messages about changes of status of private conversation.
[Azoth OTRoid] Tiny fix for type of variable.
[Azoth OTRoid] Added error handling when libotr 4.x is used.

Notify user about important errors, but do not silently ignore them.
[Azoth OTRoid] Small cosmetic changes.
[Azoth OTRoid] Small cosmetic changes.
[Azoth OTRoid] Better error handling when libotr 4.x is used.
[Azoth OTRoid] Some cosmetic changes.
[Azoth OTRoid] Better error handling when libotr 4.x is used.
[Azoth OTRoid] Fixed build with GCC 4.7.x + some cosmetic changes.
Merge remote-tracking branch 'upstream/master' into otroid-fixes
[Azoth OTRoid] Fixes after changes in API.
[Azoth OTRoid] More user notifications.
[Azoth OTRoid] Style fixes.
[Azoth OTRoid] Some cosmetic changes.
[Azoth OTRoid] Show pre-formated text.

Show pre-formated text instead of plain text when unencrypted message is
recieved during active OTR session. This magic hack is required only for
libotr 4.x to force all work as in libotr 3.2.x.
[Azoth OTRoid] Changed the order of checks when new message is received.
[Azoth] Pass optional background for colors.