implemented additional options to command line parameters

[lobis]

Implemented two optional command line parameter options for restG4:

-o output.root -> to select the output file, overwritting the rml
-g geometry.gdml -> to select the geometry file, overwritting the rml

These options can be useful for example in interactive environments such as a notebook where you would like to change these options for different cells without changing the rml.

[jgalan]

Perhaps it would be interesting to introduce a generic way to be able to control any parameter through command line.

Doing something like:

restG4 --g4metadata:gdml_file=geometry.gdml --run:outputFileName=output.root

If we achieve something generic, then we could have full freedom. I.e. I could fix also the number of events as follows:

restG4 --g4metadata:Nevents=100

[lobis]

Perhaps it would be interesting to introduce a generic way to be able to control any parameter through command line.

Doing something like:

restG4 --g4metadata:gdml_file=geometry.gdml --run:outputFileName=output.root

If we achieve something generic, then we could have full freedom. I.e. I could fix also the number of events as follows:

restG4 --g4metadata:Nevents=100

I think this is a great idea.