Version 7.8.5 Release Candidate

This release fixes a number of performance issues and adds several RPCs.

Please file issues for any problems.

Changes:

• Multi TCP connection bootstrapping
• Faster startup by using cached balances instead of calculating them.
• Added Callback RPC for account change notifications
• Fixing some shutdown issues
• RPCs are processed in background threads to avoid stalling UDP handling.
• Improved build script defaults