Refactor the handling of default_url_options in integration tests

This commit improves the handling of default_url_options in integration
tests by making behave closer to how a real application operates.

Specifically the following issues have been addressed:

* Options specified in routes.rb are used (fixes #546)
* Options specified in controllers are used
* Request parameters are recalled correctly
* Tests can override default_url_options directly
Merge route requirements

This was fixed upstream in rails@9b4514c
Escape format, negative_format and units options of number helpers

Previously the values of these options were trusted leading to
potential XSS vulnerabilities.

Fixes: CVE-2014-0081

Conflicts:
	actionpack/test/template/number_helper_test.rb