Fixed seg fault on exit due to MainWindow singleton
Adjust scalings of splitter elements
Generalized the use of Mapper from within DestinationGLCanvas
Added method MainWindow::updateAll() to update the canvases
Small fix: was using mapping id instead of layer id in addLayerItem() call
Add map of mappers (forgot to include it in earlier commit)
Replaced signal quadChanged for shapeChanged
Added basic properties widget for current selected mapper (bidirectional update of input shape vertices, though wrongly initialized)
Initialize MainWindow instance in main.cpp
Added contributed code QtPropertyBrowser
Include QtPropertyBrowser build in libremapping.pro
Include QtPropertyBrowser build in libremapping.pro
Merge branch 'develop' of github.com:libremapping/libremapping into develop