Update zotonic_install

not everybody runs postgresql 8.4, the script errors out when postgresql 9.1 is installed, which is the case when you run the script on new/recent debian servers..
Merge pull request #770 from jult/patch-1

scripts: Update zotonic_install
core: added z_proc, an interface to register processes via gproc
core: fix building the edocs
core: fixed file mode
mod_admin: Add class parameters to date picker, disable when not editable
Initial commit
Initial implementation for global config changes

See https://github.com/zotonic/zotonic/issues/767
core: z_path: fix site_dir/1, add module_dir/2
Slight doc tweak

tx @kaos :)
Fix a few more hardcoded references to priv/sites
Fix status site
Fix files subdir calculation
code: Refactor Zotonic compilation

No longer use the Emakefile, but construct Emakefile options in
code (zotonic_compile.erl).

Experimental: compilation is now done in parallel processes, for
increased speed.
Remove zotonic (enable|disable)site commands

They were undocumented and should be implemented differently.
Fix compilation, limit number of parallel compilation processes

See #767