v2.9alpha69 Parallel Release (with Mathjax support)

IMPORTANT:

These builds are not supported. Do not log issues related to them.

Special note for this release - it integrates Mathjax support from
ankidroid#5285 - we are about to merge that one so this is a
preview for wide testing. Let us know if it breaks! If you were using the Mathjax compatibility
style you should revert that and just use raw mathjax now.

This is just the personal fork of one of the developers of our beloved upstream AnkiDroid app, it is not the official app itself. Everything I work on here merges upstream though, so installing these is intended to be boring but helpful. No surprises vs the main AnkiDroid app. Hopefully I'll have time to implement the profiles feature for real but until then here we are.

DO NOT LOG ISSUES (was that loud enough? :-) )

However, feedback on the related upstream Issue ankidroid#2545 may be useful

Also, they work great for me.

Notes for fresh installs:

1. You will need to allow applications from untrusted sources to use these
   1a) Example Instructions: https://www.amazon.com/gp/help/customer/display.html?nodeId=201482620
   1b) On Oreo and later, you will be prompted on a per-app basis I think, but it should work?
2. it will not honor the storage location in advanced preferences immediately, but if you enter advanced preferences then leave without actually doing anything, it will work

Notes for upgrade installs of very old 2.8 parallel builds - The storage directory in these builds is coded as '/sdcard/AnkiDroid.A' or B or C etc. If you have changed yours for a given build letter, verify in advanced preferences that the storage directory is correct for you after the upgrade