Bug fixes and readme updates

• Add fix to :meck.unload
• Add tests
• Update README
• Add thin wrapper for :meck.passthrough

Minor improvements

• Bumped meck version to 0.8.13
• Improved documentation
• Remove implicit dependency on ExUnit

Minor edits

• Add assert_called
• Test fixes
• Version updates

0.3.0

• Bump meck to 0.8.7 and update some other dependencies
• Add setup_with_mocks macro
• Update README with more examples

0.0.3

• enhancements
  • Add optional options parameter to mocking methods. This allows
    you to specify :passthrough to meck.
• bug fix
• deprecations
• backwards incompatible changes