Wrap formatted results in quotes

This improves the readability and also allows us to transparently
handle regexes that may come from rebar.
use a separat compilation status per parallel compilation
Merge pull request #1841 from tonini/compilation_status_parallel_compilation

use a separat compilation status per parallel compilation
Add more information to generated mix.exs
Ensure LexicalTracker doesn't fail accross lexical contexts
Insert overriden dependency before any of its dependencies
Add a test case for overriden deps with cycles in umbrellas
Ensure umbrella projects sets the proper children environment
Topsort mix dependencies
Bail in `mix escriptize` if :escript_main_module is not set.