Wx cleanup

`_T` and `wxT` are not recommended on wx 2.9+, so I removed usages of those. Also, instead of using the old macro types for certain events, we just use the direct event type.

Changed some PanicAlert dialogs to PanicAlertT, since communicating why an action failed is pretty important - especially if the user doesn't know English that well, so that opens the door for translations on those strings (whenever they get synchronized to Transifex)