Change license of mb, mlprof, modulecmd, mpub, mrel, mt, mtreview,
nglfar2ccov and playdemo scripts from GPLv3+ to GPLv2+.
Align this way all files from the Modules project under the GPLv2+
license.
Consent has been obtained from copyright holder to perform such move (I
hold the full copyright for these script files).
Related to #389
In case last bugfix release was made from a branch not parent of the
current branch from which the next release will be rolled out. List all
tags and get previous version name from the second to last position.
