make --iocp and --ssl options mutually exclusive

ProactorEventLoop is incompatible with SSL
Merge pull request #49 from zed/master

make --iocp and --ssl options mutually exclusive in the srv.py example
prepare release
Fill list of known contributors
Merge pull request #51 from asvetlov/master

Fill list of known contributors and make tag for 0.7.2
simple http proxy working
removed copypaste from ProxyConnector.connect
removed proxies from request method
fixed param name
added tests for http proxy
Merge pull request #52 from mind1master/master

Simple HTTP proxy support
prepare release
Fix docs generation
Fix docs version, reflow api doc page
Add ./build into git ignore list
Fix #57: Get rid of timeout parameter in aiohttp.client API
Add missing note in CHANGES.txt
Add multidict module
exception refactoring #22
multidict pep8 and tests