Add a diagnostic function "xdebug_info()", which collates information about set-up, and also includes information for when things go wrong.

The following information should be available through it:

• PHP and Xdebug version, SAPI, 64/32bit, and ZTS/NTS, and used ini files (if possible)
• Which mode Xdebug is in.

And the following problem situations:

• Unable to open files. Add information about ownership, and permissions of directories is possible
• Debug connection attempts. Add host names, ports, which headers have been tried.
• Breakpoints set outside the directory of the original "fireuri", taking into account that if it's a "public_html" (or variant thereof), then consider the root one extra directory up.