Work around wsgiref bug

This will allow tests to pass with most recent WebTest
First test passes
File uploading tests work
Link extraction implemented
test_browser.py passes
Cookies ported to webtest
Fix test_browser to use updated API
Support for webtest >= 2.0.1
41% of README.txt covered
50% of README.txt covered
54% of README.txt covered
72% of README.txt passes

Form handling tests pass
89% of README.txt covered

Handling of image controls, forms and minor fixes.
100% of README.txt passes!
wsgi tests passes
Dead code removal

Also, host access checks are moved to main Browser class, support for
over-the-wire requests (untested).
More tests pass
Remove mechanize from dependencies
over_the_wire.txt passes
fixed-bugs.txt test passes