* rewrite nginx parser to allow everything that nginx does
* also make changes in tls_sni_01.py
* add test case with
* allow embedded variables
* allow empty ${} variable
* fix quotes
* un-special case if
* update all tests to reflect current parsing
* escape in QuotedString after merge
* add test cases for variable weirdness that are almost certainly nginx bugs
* update regex for correct variable rules
* close paren doesn't invoke last_space
* Make test file valid Nginx syntax
* Restructure add_server_directives to take a vhost as argument. This is the first step towards fixing vhost selection in nginx.
* Save path to vhost in file while parsing in get_vhosts().
* Disable creating a new server block when no names match.
* Make parser select vhost based on information in the vhost it found previously, rather than searching again for a match.
* Make add_server_directives update the passed vhost
* Update boulder config to pass test
* Add testing code for the _do_for_subarray function
* documentation and formatting updates
