subdomains in path causes incorrect link URL

Issue Summary

first of all, awesome module. Thanks for creating it.

The issue is that if the path to the drupal installation is of a subdomain and it exists in the full path then this causes visual backtrace to select the wrong $current_trace_number for the menu link "Generate Backtrace Data for this Page Load"

if the full path to the drupal installation is
/var/www/vhosts/username/module.mysite.com/httpdocs/

and the trace.12345647.xt files are stored at:
/var/www/vhosts/username/module.mysite.com/logs/xdebug/trace/trace.1234567.xt

then inside the function visualize_backtrace_block (module visualize_backtrace.module line 148) the system for detecting the location of the link
[code] // Get the trace log number by striping out number from /tmp/trace.####.xt file.
$current_trace_number = explode('.', xdebug_get_tracefile_name());
$current_trace_number = $current_trace_number[1];[/code]

the $current_trace_number[1] causes the link to pick the name of the site 'mysite' instead of the timestamp '1234567' as the link location.

This causes the link to fail.

Suggestion for the code:
[code] // Get the trace log number by striping out number from /tmp/trace.####.xt file.
$_file_name = explode('/', xdebug_get_tracefile_name());
$_file_name = array_pop($_file_name);
$current_trace_number = explode('.', $_file_name);
$current_trace_number = $current_trace_number[1];[/code]

get the filename by its location at the end of the path first to avoid this issue.