store a PluginManager rather than a MarbleModel internally
remove quitZoom-to-quitRadius settings conversion code

Since commit 600cd553abfb2f212effbac1e2c07392e3b3cd49 the radius rather than the zoom value is stored in the settings.
This patch removes code which converted the "quitZoom" value into a radius value for maintainance reasons.
So if a user didn't start up Marble for half a year, the "quitZoom" settings value will be lost and a default radius will be used instead.
Download Progress Bar for Marble Qt

BUG: 310051
REVIEW: 109866
Normalize SIGNAL and SLOT signatures

REVIEW: 108636
Open links in the legend in an external browser

BUG: 317927
Spare repaints on repeated size changes using the same value
QtMarbleSettings
port declarative widget to MarbleMap; FIXME: no input handling yet
PinchArea: pinch to zoom + pinch to rotate
MouseArea: panning with left mouse button and zooming with middle mouse button
disable PinchArea
remove PinchArea.enabled
qCeil