Merge pull request #1883 from alco/list-delete_at

Implement List.delete_at
Tidy up list docs
Update CHANGELOG
Improve EEx docs
remove `.git` suffix for `:github` referenced deps

the `:github` option fails if a partial path with `.git` appended is
provided.

Fixed this to provide an example that works (if the "barbat" repo actually existed)

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>
Updated 'make docs' to latest ex_doc cli args
Merge pull request #1886 from jwarwick/make_docs

Updated 'make docs' to latest ex_doc cli args
Make inspect in general 20% faster

There are two main optimizations:

1. We have optimized Module.concat/2 (it is roughly 100% faster)
2. We have optimized rendering of Inspect.Algebra by skipping
   the intermediate s_doc representation. This reduces memory
   allocation and skips one extra pass on rendering.
Update typespecs in Inspect.Algebra
Add Enum.reverse/2
`mix deps`: Display refs pointing to the checked out commit for each dep