Sound plugin: Ability to Enable/Disable plugins

[jfgilliam]

Although you can disable the build in plugins using the settings.txt->simplugins variable by placing them in the list with an exclamation mark in front of them, I want there to be an easier way. Therefore, add support for each plugin name to be a true/false variable. Example:

Sounds.Shift = true
Sounds.PitSpeedLimit = true

This changes the settings.txt->simplugins variable meaning, such that, only plugins that are not built into the server have to be listed.

[jfgilliam]

This was added to the 1.2 BETA release dated 2016.09.29