Added File.listdir API
Added File.listdir! variation
Fixed File.listdir! to return the list, without wrapping it in {:ok, _}
renamed to ls, added unit tests
File.ls & ls! tests now cover non-existent directory situation
Use at least 2 runners regardless of the number of schedulers
Improve docs and exceptions for regexes
Ensure unquotes are respected in the test macro
Also allow unquoting on setup and teardown callbacks
Fix is_record tests to check tuple_size before accessing the first element
Improve error messages
Unicode split
Update binary_to_ macros to use binary_to_ functions in R16B.

Also add support for float_to_binary/2
Include more recent Erlang versions into Travis-CI configuration
Merge pull request #914 from yrashk/binary_to_updates

Update binary_to_ macros to use binary_to_ functions in R16B.
Improve documentation for the String module
Make record types in record public as well
Improve docs for function
Add documentation on @record_fields and @record_types to defrecord
Check also Kernel.SpecialForms in h(). Fixes #906