v0.1.4

Miscellaneous maintenance

• Silence Elixir 1.5 deprecation warnings over Kernel.to_char_list/1 (cf. elixir-lang/elixir#4909, elixir-lang/elixir#4582). Since the mixfile here locks us to Elixir ~> 1.3, it should be safe to just use Kernel.to_charlist/1.
• Bump the combine dependency due to errors reported in #5.