Deprecate ListDict and access for lists with non-atom keys
Do not add spaces after { and before }

This makes the source code consistent with the result
returned by inspect/2.
No longer support tuples in function_exported?
Move preferred_cli_env to a map
Add String.split_at

While it is straightforward to split a string given
an offset in bytes from its beginning like this

    <<left::[binary, size(offset)], right::binary>> = string

splitting at grapheme boundary or using negative offset
is not so simple. Hence this function.
Merge pull request #2185 from alco/string-split_at

Add String.split_at
Correct Enum.group_by/3 typespec
Inline some map calls
Fix compiler crash for some map literals
mix clean works accross environments
Remove records from IEx
Remove records from EEx
Docfix: write error
Merge pull request #2186 from jsvisa/exunit_case_docfix

Docfix: write error
Use project :description if one is available
Deprecate :env in project config and support MIX_EXS
Pass the relaxed option when downloading rebar

Closes #2152
Make iolist_to_binary/iolist_size a soft deprecation
Fix Elixir tests on Windows, closes #2190
Fix bug in for comprehensions