replaced return value of DocumentManager::addDocument with a signal
moved loading to a separate thread
replaced return value of removeDocument with a signal
added basic loading GUI
moved new flag from setupData function to Document constructor
more cleanup of document setup
moved load code from Document to Loader class
content file loading progress bar
Merge branch 'master' into load

Conflicts:
	apps/opencs/view/doc/viewmanager.cpp
split up load function in a start and continue part
record loading progress bar
added cancel button to loading window
intercept close button clicks in loading window
handle exceptions thrown during loading and report them to the user
fixed a mixup in CSMTools::Tools constructor/destructor
Merge branch 'operations' into load

Conflicts:
	apps/opencs/main.cpp
	apps/opencs/model/doc/document.cpp
added load error log
display load error messages in loading window
improved layout of loading window
generate error messages when encounting non-critical problems during load