cmake: add mcf_util

NOTE: this is a candidate for the stable branch
Merge pull request #535 from karolherbst/mcf_util

cmake: add mcf_util
version: note mcf_util in changelog
version: move some rc1 lines to the right rc* and add missing notes
js/playList: parse rating to float

the custom sort function is comparing strings. String comparision in JavaScript is fine as long as both strings have the same lenght and the decimal mark at the same position.

But "10.0" was the only case violating this. "10.0" < a is returning false for all a's matching ^[0-9]\.[0-9]$

fixes #374

v2: we need to handle the rating coloumn explicitly, also remove this dirty eval hack with an associative array access

fixup