Added WSGIPassAuthorization option to vhost.
Added The ProxyPreserveHost option to vhosts.
Updated readme with WSGIPassAuthorization information, updated spec and
rspec tests for WSGIPassAuthorization.
added documentation and test for ProxyPreserveHost option
Merge pull request #694 from Conzar/master

Added WSGIPassAuthorization option to vhost.