Cannot generate custom graph before 6 months from present

[kizniche]

To get commit 572dfeb working, I had to temporarily make custom graph generation only work for the past 6 months. It should be an easy fix once I look at that part of the code, but for now everything else works from this major overhaul of the custom graph generation.

Essentially, the custom graph generation was handled in PHP. It is now handled by the Python function that generates the preset graphs on the Graph Tab.

[kizniche]

fixed in 0737db7