Merge branch 'license' into 'master'

Updated license file to LGPLv3.

See merge request !29
3 jobs for master in 5 minutes and 20 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #19842
osx-sierra
OSX

00:03:02

passed #19841
ubuntu
Ubuntu-master

00:04:27

55.1%
passed #19843
win7
Win7-vs14

00:05:20