Add ability to disable buttons
Add setting to disable some relay buttons (but still see their status)
Split preferences file into multiple files for easy maintenance
Added ability to enable/disable expansion relay ports

The ability to enable and disable expansion relays did not exist in the preferences screen, so it was added.
Also reorganized the Controller Information preference page and re-grouped the settings to make more sense.
Grouped all preference Keys together to simplify translation of strings
Updated changelog
Added ability to reset ports back to enabled state

Closes #67