Moved installation of file templates from privileged script to a new build phase

The installation of the plugin currently installs the templates into both the system Developer directory and the users ~/Library/Developer/Xcode/Templates directory using a script which is run as root.  This means that the templates added to the users Templates directory are owned by root and don't have permissions for the user to modify/delete the files.

I have added a new build phase which copies the file templates to the users directory without root privileges so that they are owned by the user.  The class templates are still installed by the privileged script.

You may want to implement this in a different way so feel free to do this in a different way.  However, I don't believe it is correct to place files in a home directory that the user can't remove.