[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
Also, adding them to requirements.py will allow users (for now me) to know which dependencies are required. Adding them here will not help users