Current progress of GameController API integration. Related to issue #37.

Still a lot of work to do to make this more manageable. Definitely
need to move more classes into separate packages/folders.
Fixed a couple of signal problems when built against SDL 1.2.
Changed GCMappingDialog to stop fake presses. Altered raw event usage.
Moved GameController classes to a new folder.
Initial work on hotplug support.
Minor tweaks for GameController name display and throttle check.
Put GameController mapping strings into main app settings file.
List of recent configs is now tied to information given by SDL.

The order of searching is GUID => Name. GUID is only
relevant on SDL 2 so the name given by SDL is used
as a backup value. Indices are no longer used.
Allow command-line profile loading to be specified via GUID or name.
Minor changes in name displays. Throttle change in JoyAxis.
Updated docs.
Changing current filename specfication. Device type is added to the filename of a profile.
Updated README.