Add parsing of xdebug function trace files

```
Add parsing of xdebug function trace files. These files tend to cover what 
regular .cg files provide. The most matching format is 
xdebug.collect_params=0 and xdebug.trace_format=1.

http://www.xdebug.org/docs/execution_trace

```

Original issue reported on code.google.com by `Alexey.K...@gmail.com` on 16 Nov 2008 at 4:10
