* Rename ButtonSchema to PadSchemaControl, create ButtonSchema subclass, rename
AnalogSchema to AnalogStickSchema, and make PadSchemaControl abstract
* Replace switching on PadSchemaControl.Type (enum PadInputType) with type
checks
* Refactor and merge VirtualpadTool.CheckPads() into .CreatePads() (it was
easier than just using type checks in the old algorithm)
* Move members from PadSchemaControl to subtypes and cleanup