TextWindow.cs: fix an out-of-bound exception in some case when mouse hover Chat area. Happen because some counting variable wasn't reset to 0 when re-Initialized (This is due to recent changes. This exception doesn't seem to cause any crash tho...)

Minor tweaks:
SettingsTab.cs: make SettingTab's splitcontainer don't throw exception if downsized to point it have no more room to go to.
MainWindow.cs: set a minimum size. Was set to 300x200 so there's no way to totally squish all element to point of causing any exceptions.
BattleChatControl.cs: add try-catch for BattleUserStatus event to catch an exception. Trace from TasClient.cs for BattleUserStatus is not complete due to Invoke or Threading something...