GSoC Week 7: Nothing much, a couple of small fixes

#phpMyAdmin, #gsoc15

I couldn't do much for the whole week, but finally yesterday, on Sunday, I could do something. Not much, though.

Tasks done

Format backtrace only when required in debug console
Show loading message on back action with html5 history API

Upcoming tasks

Look if some performance improvements can be done for page-related settings

Notes

I found that when SQL debugging was on, my server export page took a really long to load. It was because of the large number of queries executed for the export alias support "Rename exported databases/tables/columns" option. To my surprise JavaScript and DOM was taking too much time to create the nodes for traceback for each and every query. I tried to fix it with #1785.