fix focus problem

used id.forceActiveFocus() in click event of MouseArea for every custom object to take the focus of the MainWindow
Merge branch 'develop' of github.com:buttleofx/ButtleOFX into develop

Conflicts:
	buttleofx/gui/graph/qml/Clip.qml
	buttleofx/gui/paramEditor/qml/ParamBoolean.qml
	buttleofx/gui/paramEditor/qml/ParamChoice.qml