perf(Request): Use a list comprehension and don't lowercase the headers

List comprehensions are faster than generators. Also, there is no
need to lowercase the header name, since headers are case-insensitive
after all.
fix: Add output encoding to tests for Python3

In certain environment setups python 3 will detect the appropriate
output as ASCII and will fail when trying to write a unicode string.
Override this by forcing UTF-8.
chore: Send Travis notifications to IRC
doc: Clarify WSGI app variable in README examples
Ensure long description is Unicode string in setup

Python 3.3 is not able to properly install Falcon
due to UTF-8 characters in the README.rst file. The
characters are fine, we just need to be sure to decode
the open('README.rst', 'rb').read() bytestring as a
unicode string.

An example of the setup failure can be seen here:

UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 586: ordinal not in range(128)

http://logs.openstack.org/40/55040/2/check/gate-solum-python33/02f9aca/console.html
Merge pull request #201 from jaypipes/utf8setup

Ensure long description is Unicode string in setup
Merge pull request #188 from jamielennox/py3-tests

fix: Add output encoding to tests for Python3
Merge pull request #193 from kgriffs/master

perf(Request): Use a list comprehension and don't lowercase the headers
feat(api): allow add one responder as a route

The new API add_proxy is similar to add_route, but only takes
one responder, and passes all allowed HTTP methods to such a
responder.

The API simplifies building proxies, especially the ones forwarding
all requests to other nodes.