Change the Path module to work only with char_data and always return binaries
Convert File and IO to char data, use +fnu flag by default
Provide List.from_char_data! and String.from_char_data!
Rename iolist_* to iodata_*
Properly @spec functions in Path
Typespec and allow char data in File functions
Properly indent chunks in System module
Merge branch 'jv-char-data'

Conflicts:
	lib/eex/lib/eex/tokenizer.ex
	lib/elixir/lib/file.ex
	lib/elixir/lib/kernel.ex
	lib/elixir/lib/record/extractor.ex
	lib/elixir/lib/string.ex
	lib/ex_unit/lib/ex_unit/doc_test.ex
	lib/mix/lib/mix/archive.ex
	lib/mix/lib/mix/dep/fetcher.ex
	lib/mix/lib/mix/dep/umbrella.ex
Update CHANGELOG