* Implemented one single gloabel Lua VM for the entire CampVisApplication instead of one VM for each pipeline.
* The global Lua VM has a "pipelines" table/array, holding the pointers to each loaded pipeline
* ScriptingWidget support cycling through last executed commands via the arrow keys
* LuaVmState supports redirecting Lua's print() function to a custom one that uses tgt::Logmanager for printing (just as proof-of-concept). This shall later be extended to pass all Lua output to the scripting console.