[feature] Use sanitized uri as source instead of 'Symfony'

This replace source part of the files generated by Xhprof.
For now files are named like : "539029914bbb1.Symfony.xhprof", which is not really explicit when looking for a run.
With those changes for this url : 
```
http://www.mydomain.com/path/to/my/page?__xhprof&some_query_parameter=some_value 
```
run filename will look like 
```
53903af058742.http-~www-mydomain-com~path~to~my~page-__xhprof-some_query_parameter-some_value.xhprof 
```
Which is not perfect but more understandable when looking the run list