Step 2 of report refactoring: Put overviews in their own files

As requested I've pushed all the reports to their own files.
This cleans up A LOT of code for the html, csv and text generation in report.
The next step should probably be to have the overviews separate their data and formatting functions and have them automatically register themselves with report.

Overview and Report still have a lot of stray 'helper' methods, but most of the global variable scope issues have been fixed.