Alda on Raspberry Pi

[daveyarwood]

Continuing from conversations in the Alda Slack group, tracking the work to be done here:

• Add ARM builds to client/bin/build (currently only on the arm-build branch)
• Tune JVM options so that alda-player processes use less memory?
• Add arm64 release testing to CircleCI build (looks like they don't support 32-bit ARM, so can't test ARM 7)
• Update Alda API to include arm-7 and arm64 releases
• Ensure that alda update can find the right releases for ARM 7, arm64
• Ensure that ARM releases are included at alda.io/install