bugfix: CVCenterLoadDialog was throwing an error
if a setup had been loaded previously and another one was loaded later
dur to midiSources being nil

Signed-off-by: nuss <st9fan@gmail.com>
Merge branch 'CVWidgetMS' of github.com:nuss/CVCenter into CVWidgetMS
keycodes and modufiers under OSX

Signed-off-by: nuss <st9fan@gmail.com>