Added global variables (DF y OF) to the command line.

Now, the number of directory facilitators and Overbooking factor can be
specified through the command line by defining the global variables:

 - df: number of directory facilitators, and
 - of: overbooking factor.
 
gridlabd file.gml --define df=1 --define of=2.0
Added the capability to print simple reports to 'reporty.py'.
Added new fields to the script Report.

Added the number of invitations to auctions that were ignored. This change also adds the number of producers that were discarded (that didn't achieve to allocate any resource).
Added new fields to the script report.py.

The script reporty.py now adds fields such as the number of: empty acutions, producers, consumers and cancelled auctions.
Updated the scripts.
Added 'rnd' as a new parameter of the command line.