Bug Fixes and improvements to --xp-mode

- Fix #425 - copying files even when they already exist on a remote server
- Fix #426 - daemon.js scheduling error in advanced --xp-only mode when we don't have room to schedule all recovery and grow threads.
- Fix #427 - When exp farming, allow the last target to use multi-server mode (allow thread splitting), which should make better use of available ram on the network.
- Fix #428 - Preferred server order gets messed up when home is filtered out
- Fix #429 - Not using advanced --xp-mode in BN8
- In advanced mode, schedule weaken threads before grow threads in case there ends up being not enough RAM - missing the former would put us in a spot that's slow to recover from.
- Improved verbose logs for --xp-mode
- Refactor: move where we double the home reserved ram to run this check less frequently
- Refactor: use let or const rather than var everywhere