Fix double elaboration of DUT when using the interpreter (#154)

* Fix double elaboration of DUT when using the interpreter
setUpFirrtlBackend was failing to use the previously emitted firrtl code

* Fixed further problem, that although proper pass was not called, the resultant low firrtl was not used.
This is now fixed.
interpreter backend now forces low compiler to be called.
this fix required one of the driver tests to fail, that is fixed
also fixed some intellij files being tracked by git that shouldn't be
made work