some more license mappings

Hi,
I've added a few more license mappings, such as:

  'GPL (v3 or later)' => 'GPL-3+'

prompted by trying to get the copyright file for freeswitch to be somewhere near complete.  That also required some patches to licensecheck from devscripts, but mostly getting it to shut up about false positives, so this patch should be fine even with an unpatched licensecheck.
Cheers, Phil.