doc: Update design goals in README to be in sync with website
refactor(testing): Rename "script" argument for create_environ to "app"
refactor(testing): Factor out classes into their own modules.\n\nFixes #75
refactor(testing): Factor out classes into their own modules.

Fixes #75
Merge branch 'master' of github.com:racker/falcon
fix(Request): content_length not an int
fix(StartRequestMock): callable does not accept exc_info per PEP-3333
fix(testing): create_environ not setting all PEP-3333 vars
feat: Before hooks, also CherryPy benchmark
test(bench): Randomize ordering between each round, enable gc