[Frontend-GNOME] Make Buffer a local variable in MessageTextView.CheckBufferSize()
[Frontend-GNOME] shrink and grow topic text field depending on size of topic
[Frontend-GNOME] removed unnecessary code

a wrapping textview will never have a horizontal scrollbar
the vertical is automatic anyway (see Entry)
[Frontend] refactor tab completion

Move tab completion from the individual frontends into a set of classes in
Frontend. Implement cycling through nicknames in irssi mode.
[Frontend] Fixed make build
[Frontend] Fixed build on .NET 3.5
Merge pull request #45 from oli-obk/feature/autoresize_topic
[Frontend] fix erroneous completion across chats

When using tab-cycle nick completion mode, successfully triggering completion,
then switching to a different chat, then triggering completion again would
supply a nickname from the previous chat.

Now, if the user switches to a different chat, the completer forgets the
previous nickname list (and refuses to cycle through the completions until a
completion with different input is triggered).