Update minimum version of Hashie::Mash, fixed performance issue with requests carrying a large payload, #494.
Expanded test matrix to more rubies.
Upgraded Rubocop to 0.20.1.
Convert specs to RSpec 3 syntax with Transpec

Converted specs to 3 syntax using the Transpec gem. Additionally, updated test in endpoint_spec.rb on Line 108 to check for nil rather than attempting to match on nil.
Merge pull request #619 from danielspector/transpec-rspec-update

Convert specs to RSpec 3 syntax with Transpec
Adds Guard with RSpec/RuboCop
Update README.md
Merge pull request #623 from edelgado/master

Added a Table of Contents to README.md
Moved buidl status above the fold.
Adds Grape::Endpoint.before_each for pre-run endpoint config. Refs #396
Merge pull request #397 from intridea/endpoint-setup

Adds Grape::Endpoint.setup for pre-run endpoint config.
Add mutually exclusive params validation
Merge pull request #626 from oliverbarnes/mutually_exclusive

Add mutually_exclusive params validation