licq: pass signals and events as shared_ptr's

Avoids memory leak in case plugin isn't ready to handle signal or it it has
been shutdown
licq: pass signals and events as const pointers
Merge branch 'master' into signals-as-shared-ptr

Conflicts:
	licq/src/plugin/tests/generalplugintest.cpp
	licq/src/plugin/tests/protocolplugintest.cpp
	qt4-gui/src/core/signalmanager.cpp