Trigger recompilation of depending targets when needed.

Fixes issue #22.
Remove unused nodes from node tree.
Use C++11 thread routines instead of pthread.

Also fix a dead lock caused by the refactor.
Better job names, still ugly but better than before.
Use _output from lua instead of get the output name direct from Compiler interface.
Remove luaPushTarget from NodeTree and use the one on MeiqueScript.