The custom bin path was set in multiple places. Each time, the line
was identical and supposed the use of a /bin/sh emulation with a
common extension. To reduce duplicated code and support other
platforms, the custom bin path is now set in a dedicated script that
can be source'd.
The WM not being started with a login shell, the user preference aren't loaded. For example, awesome's quick exec bar cannot profit from the .zshrc custom PATH. Setting it in the .xinitrc solves this problem.
