This is necessary because the standard library which is distributed with
lumail (the lumail core configuration so to speak) is written for lua5.1
apparently.
The website states 5.1 or 5.2 or 5.3, but 5.2 fails because "loadstring"
was deprecated in lua 5.2.
Signed-off-by: Matthias Beyer <mail@beyermatthias.de>
Includes:
* Package gets a flag to use the debug build
* install phase installs all lua scripts from the package and makes
lumail find them
* global configuration which is shipped with the package can be
overridden, if desired
* parallel building enabled
