Update to 3.1.2. Set LICENSE. Clean up. Make optional parts options.

Version 3.1.2 -- the "Skip the impersonations" release.
* Contains translation updates and small bug fixes.  No new features.
* ca, cs, de, fr, he, it, nb, nl, pl, pt_br, ru, sk, sv,
* fixes a failure in 'Check & Repair Database'
* fixes to Gramplets
* fixes to CLI regressions
* fixes to Latin1 characterset in Graphviz reports
* fixes to many reports
* fixes to the clipboard
* fixes to NarrativeWeb
* fixes to importing from older XML files
* fixes to ensure GRAMPS continues to run on newver versions of Python

(wiz)