Uniform use of whitespace after commas on codebase

This make easier to read and also follow some standard in the code
Merge pull request #1259 from elixir-lang/whitespaces

Uniform use of whitespace after commas on codebase
Update docs for Macro.expand
Update CONTRIBUTING.md language
Don't assume terminal availability in ANSI doctests
Merge pull request #1261 from alco/ansi-doctest

Don't assume terminal availability in ANSI doctests
Improve mix test to rely on possible multiple messages
Return Foo for __MODULE__.Foo outside of a module
Ensure defmodule :atom does not define an alias
Ensure imports inside quotes are properly registered, closes #1225
Improve error message matching on local.uninstall with archives
Avoid race condition on CLI tests
Ensure errors point to the proper -> clauses

This commit changes the -> clauses representation from:

    { :->, meta, list({ list(expr), expr }) }

To:

    { :->, meta, list({ list(expr), meta, expr }) }

Now clauses can store metadata, which allows us to provide
accurate reporting information.

Closes #1215
Use the proper code highlight for functions
Follow the bullet point standard on this file
Merge pull request #1263 from elixir-lang/docs-standard

Change the bullet points on code.ex to follow the standard on this file
Fix rebar config scripts evaluation

Scripts are evaluated using the dependency directory as current directory

Closes #1262
Merge pull request #1264 from edgurgel/mix-rebar-scripts

Fix rebar config scripts evaluation
Do not check in utf8 directories into source control
Make sure all Erlang parameters are extracted and parsed in elixir.bat