PKGBUILD fixing and cleanup

Matching the guidelines from https://wiki.archlinux.org/index.php/VCS_PKGBUILD_Guidelines#Git

You should consider renaming the package cmdevcenter-git. This is why I used _pkgname in the script.
To do that, you have to [email the TUs](https://mailman.archlinux.org/mailman/listinfo/aur-general) and ask them to rename it.