Bump to 0.12.3-dev
Ensure heredocs are allowed in calls, closes #1998
Guarantee nullary funs/macros are allowed in guards, closes #1997
Remove deprecated code
Remove @hidden in mix tasks

Instead, we can use the presence or abscence of @shortdoc
to specify if the task should be shown or not.
List iex -S mix at the bottom of mix help
Change precedence of <- to be the same as other generators
Add index reflection to private records

Example:
defrecordp :user, [:name, age]
user(:age) #=> 2
Simplify diverge/override mechanism in Mix.Deps
Deprecates binary_to_term and term_to_binary in Kernel.
Merge pull request #2004 from rcoppolo/deprecate-term-binary-in-kernel

Deprecates binary_to_term and term_to_binary in Kernel.
Ensure ExUnit doesn't hang on linked failures

Thanks to @pminten for reporting this issue.
Change HashDict implementation to use tries with compound nodes

The new implementation is basically a tree of tuples (tries) but
they allow compond nodes (a node with a key-value pair and a
sub-tree). This removes the need for node-expansion and also simplifies
the design structure to not require multiple stages nor buckets.

The end result is a faster HashDict implementation (about 10% faster
on access, 30% on updates), which is still small for small dicts
but about 30% bigger for large dicts (in terms of memory) and with
a much simpler implementation.
Clean up DictTest implementation

Before this commit, DictTest used too many helper functions
and  used assertions in the opposite order.
minor typo in doc
Merge pull request #2009 from xumingthepoet/master

minor typo in doc