[WIP] Feature/fix libmproxy 1269

Issue #1269 

 - [x] spiderman works with libmproxy
 - [x] localproxy works with libmproxy
 - [x] sqlmap works with libproxy
 - [ ] Add more unittests for Proxy and w3afHandler
Is jinja template rendering this? Are we sure that the parameters are properly HTML-encoded to avoid XSS?