Show unsupported selected presets for mac-avcapture

Configured presets that are unsupported are now preserved in the user config,
but listed as disabled
Add disconnected (selected) devices to device list for mac-avcapture

This requires the (localized) device name to be stored
Implement preset auto select notification for mac-avcapture
Disable default device selection for mac-avcapture

Since adding a source now opens the config dialog for that source
the convenience gain from having a device automatically start capturing
is outweighed by the inconvenience from having captured images
unintentionally recorded/streamed
Merge pull request #128 from palana/mac-avcapture-settings-changes

Update mac-avcapture to use recent property and data changes
Rename GS_ERROR_MODULENOTFOUND

Rename GS_ERROR_MODULENOTFOUND to GS_ERROR_MODULE_NOT_FOUND
Fix 'potentially uninitialized' warning on var
linux-xshm: Fix potentially uninitialized var.
Fix cursor position in xshm plugin