raise properties pane

[Harald Albrecht]

Hi Evert, Jesse, all,

a quick note so your blood pressure doesn't raise with the properties 
pane with the recent git master commit :)

We've now made the "raise properties" configurable, you'll find three 
new checkboxes in the config dialog, tab timeline. Select those timeline 
elements which, when selected, should raise the props. We default now to 
the classic Kdenlive behavior, that is, raising on clips, transitions, 
tracks. Just untick "clips" and you're set.

Best regards,
Harald