moved alarm/xbmc-imx to alarm/kodi-imx; updated to Helix stable

This moves xbmc-imx to kodi-imx and updates the PKGBUILD to use the stable Helix branch.
It also removes the git dependency from the build process and builds straight from the release tar.

Maybe a replaces=("xbmc-imx-git") should be added. I need some input on that

Happy holidays!