mesa-demos: convert to new package format

Signed-off-by: Stephan Raue <stephan@openelec.tv>
mrxvt: convert to new package format

Signed-off-by: Stephan Raue <stephan@openelec.tv>
Merge branch 'master' of github.com:OpenELEC/OpenELEC.tv
- revert last commit
- never install devtools
Merge remote-tracking branch 'upstream/master' into frp