fix(setup): don't warn re: cython under pypy

When installing Falcon using pypy, don't bother checking for cython -
it's meaningless for pypy.
fix(setup): NameError -> AttributeError
Merge pull request #169 from sorenh/master

fix(Request): Allow for query param names with dots
chore: Add Soren Hansen to AUTHORS. Thanks sorenh for contributing!
refactor(setup): --cruft, with_cython -> CYTHON
Merge pull request #171 from cabrera/pypy_no_warn_cython

fix(setup): don't warn re: cython under pypy

Fixes issue #167
feat(Request): Also accept query params from POSTed forms

Fixes #170