The actual problem was combining the values from the date and time
pickers incorrectly. The uninteresting parts of the returned wxDateTime
need to be ignored and the WX documentation says so for the time picker.
I also cleaned up the handling of both widgets a bit, removing redundant
member variables in the process, in order to not risk correctness.
This is only ever queried and not set outside of the Core.cpp, so this
should just be hidden internally and just have a function exposed that
allows querying it.
Prior to this, ConfigMain.cpp was a large (52KB) cpp file that contained all of the UI setting code.
This breaks up the config code into subclasses of wxPanel, which are then just instantiated to add to the settings wxNoteBook. This keeps all the settings categories separated from one another and also cleans up the code in general.