v0.8.0

Changes

• OAuth dependency library is updated (#63).
  • Adding {:oauth, github: "tim/erlang-oauth"} in mix.exs becomes not required.
• Configurations for proxy is simplified.
  • https://github.com/parroty/extwitter#proxy
• Fix [mix bench] task error and library updates.
  • Update benchfella and remove some warning notes about setup/teardown.