Stereo System 1.7

1. Added play pause functionality.
2. Added volume control functionality that is independent of the 'Music' volume slider under the 'Audio->Volume' settings.
3. Added the ability for the system to turn on and off based on the ignition level of the vehicle. Subsequently, this caused for the removal of it disabling when the vehicle's engine stalls.
4. Made it so that if the system shorts in water, upon restoration it will resume a track from where it left off when the system shorted.
5. Generalized the file structure of the mod so that it will work in ANY vehicle without requiring it to be manually added, thus allowing it to work on mod vehicles as well.
6. Made it so the controls will now appear under the 'Vehicle' section of the 'Controls' settings thus allowing for global bindings across all vehicles.
7. Heavily revised the message system so that it is more descriptive of the state of the system during any relevant input.
8. Made it so the mod will not work in non player vehicles (i.e. traffic or AI controlled vehicles) or props.
9. Previously, if there were non .wav and/or .mp3 files in the music folder, a track could appear more than once in a row in the playlist when turning off shuffle mode which subsequently excluded other tracks. This bug has now been fixed.