Remove double spaces from shaders' names in settings.
Use consistent settings names.
Rename "SnapShot" to "Snapshot".
Change old strings to MPC-HC.
Change "Gabest" to "MPC-HC".
Installer: change more strings and remove the old keys when uninstalling.
Missed `PROGID` (to be squashed)
Remove obsolete comment. (to be squashed)
CMPlayerCApp: Move registry settings from the old to the new location.

Only when we're initializing the MPC-HC key for the first time.
CAppSettings: Add versioning to settings and update any old versions.