Update default language versions; Seperate functions into file
Add add_erlang and exit_if_file_present functions
Update readme with .language_versions examples
Seperate functions in lib dir
Add elixir download function; Change erlang_tar_name to erlang_tarball
Add more details to readme; Add license
Minor formatting
Change h4 to h3
Fix link formatting
Some more formatting
Complete darkroom programming
Build in cached dirs, copy them as an installation procedure
Fix build_pack_path
Ensure build and cache dirs are present before doing anything else
silent all cd - and add some formatting
Fix erlang install command path
Fix curl options; use rebar_tarball and not rebar_download_file
mkdir erlang_build_path
curl on Heroku is really old; We don't want to touch system stuff manually; Fix has workaround for it
Fix function names