v3.0 More efficient downloading and OA status pruning

Now including the following tweaks:

• OpenApply endpoints are more reliably fetched
• Caching to avoid overloading servers

One one big improvement:
• In OpenApply, any students no longer that have indicated status now deleted from the sheet
So, if a student was enrolled yesterday but no longer, when next run that student is removed from the sheet.

Instruction on updating to latest are available in the readme.md

Link to repo