Add Krumo Support and a way to output the entire function call stack to an output file for diffs

This patch adds an undocumented option to add in 'krumo' as the fourth argument (i.e. visualize_backtrace/1232915943/hide_callstack/all_sections/krumo) -- currently only works on smaller page loads, and half loads on bigger pages.

It's kind of a brute force approach as well, and I'd welcome a more efficient way to do the conversion from a flat array to the $function_callstack_krumo_output nested array.

There's also a nice little krumo jQuery bit that I added as well in order to automatically expand the entire Krumo array.
It'd be nice if this supported expanding all of krumo up to certain depths, but need more jQuery ninja-ry for that.

I also added a way to output a text file dump of a nested array of the entire function call stack so that you could do a diff between two Drupal page loads to see what differs. FileMerge on the Mac is a nice way to view those. Doing this may have uncovered some other bugs in the module since it appears that some functions preceded by a line 0 call are skipping a level.

The way to initiate the output file creation is to add the word "output" to the fourth argument (i.e. visualize_backtrace/1232915943/hide_callstack/all_sections/output)

This creates a file in the /tmp directory called drupal_debug_1233108926.txt.

This option is also undocumented at the moment.

But the "krumo" and "output" options could stand a quick link in either the sidebar block or on the generated page.

Also removed a deprecated call-time pass-by-reference that was spitting out this error to the apache log at /private/var/log/httpd/error_log