mix escriptize: Support escript_path to specify the path on disk to write the escript to.

Fixes #714.
Merge pull request #750 from alexrp/master

mix escriptize: Support escript_path to specify the path on disk to write the escript to.
The pipeline operator is now '|>'.

Fixes #718.
Remove unused optional argument from Record.{deffunctions, deftypes}.

Fixes #744.
Support indexed Enum.map/2.
Support indexed Enum.each/2.

Fixes #748.
Enum: Use index type consistently.
Add back /> as a deprecated operator.

This commit can simply be reverted when the operator is to be removed.
Add changelog entry about /> -> |>.
Merge pull request #752 from alexrp/record-deffunctions-opt-arg

Remove unused optional argument from Record.{deffunctions, deftypes}.
Merge pull request #753 from alexrp/enum-each-map-iter-index

Support indexed Enum.{each/2, map/2}.
Merge pull request #751 from alexrp/pipeline-operator

The pipeline operator is now '|>'.
Add a stacktrace to /> deprecation
Allow protocol definitions nested inside modules
mix escriptize: Correctly set :escript_embed_elixir to true by default.
Merge pull request #754 from alexrp/master

mix escriptize: Correctly set :escript_embed_elixir to true by default.
Make IEx rely on ensure_compiled and add a fix for when the function has no docs
Also handle < and > inside interpolations
Improve hygiene for variables, related to #722
Expand aliases inside quote