Merge pull request #18 from roignac/master

Fixes
Fix AttributeError by checking if self.playlist is None
Merge pull request #20 from roignac/master

Set correct path to libgd
Remove application_id temporary: seems to collide with installed JS version
Set correct exit status for application
toolbar: correct reference to 'Done' (cancel) button
view: vadjustment -> get_vadjustment()
view: use adjustment functions instead of vars
view: updated params for makeDefaultIcon
view: correct headerBar var name