x11-wm/fvwm-crystal: upgrade 3.0.6 -> 3.4.1

• update WWW to SF
• no longer limited to python2.x

PR: 239625
Submitted by: Walter Schwarzenfeld <w.schwarzenfeld@utanet.at>
Approved by: giacomomariani@yahoo.it (maintainer timeout)
Relnotes: https://sourceforge.net/p/fvwm-crystal/code/HEAD/tree/ChangeLog