TextColor.cs: fix displaying wrong color for message with irc color

(color for irc was used for theme, moved them to fix overlap)

PrivateMessageControl.cs: fix autocomplete username not working in PM, also make background theme effect PM (and ServerTab.cs & Battlebar.cs) area too.

ChatControl.cs & BattleBar.cs: some required tweak for irc color changes.

SendBox.cs: overflowing text now grow to the right rather than wordWraped to new line (for intuitiveness)

TextWindow.cs: capture closing IRC color char

NavigationControl.cs: make button fit the Text size (make it smaller)