Implement String.capitalize/1
Implement String.slice/3
Fix the implementation of String.capitalize/2
Merge pull request #723 from mururu/string_functions

Implement some String functions
modify atom with interpolation tokenizer
add code and tests for case insensitive hex interpolation.
Merge pull request #729 from mururu/atom_interpolation

Modify atom with interpolation tokenizer
Merge pull request #730 from kimshrier/case_insensitive_hex_interpolation

add code and tests for case insensitive hex interpolation.
add octal and hex escapes for characters
IEx autocompletion should show all exported functions, not only documented ones

Closes #733
Merge remote-tracking branch 'upstream/master' into octal_and_hex_escapes_in_characters
Update octal and hex escapes for characters, char lists, and strings to all accept
the same syntax and be case insensitive.  Also relocated the character type macros
into lib/elixir/include/elixir.hrl so that they didn't need to be defined in both
lib/elixir/src/elixir_interpolation.erl and lib/elixir/src/elixir_tokenizer.erl.
Added to the erlang and elixir unit tests to test the new syntax.
Remove __info__/1 from __info__(:functions)

Closes #734
Improve message for bad function error

Closes #732
Merge pull request #731 from kimshrier/octal_and_hex_escapes_in_characters

add octal and hex escapes for characters
Update CHANGELOG.md
Fix indent
Merge pull request #738 from mururu/fix_indent

Fix indent
Add assert_receive and refute_receive to ExUnit
Add Dict.put_new and Keyword.put_new