Maintenance Update Phoenix (0.9.12.0)

This maintenance release is recommended for all nodes, but is not urgent.

A future update (not yet scheduled) will begin enforcing the minimum relay fee equal to the current default fee, so nodes that have not yet updated to a minimum of 0.9.12.0 will then be disconnected and banned.

Fixes some Windows build issues
Add option to disable blockchain auto-save (useful to reduce swapping on low-memory nodes)
Prioritize transactions by fee/byte
Disable relay of transactions with legacy fee lower than current default

https://github.com/aeonix/aeon/releases/tag/v0.9.12.0