Update registry ship in mining command

Bug was showing up where mining wasn't being reset after
mining was finished
UI: add seemless audio looping, audio for various events/actions

Newly added audio for:
- movement selection, progress, arrival
- triggering a jump gate
- selecting an attack target
- beginning entity construction
- docked ship to station
- transferring resources
- mining in progress
Accept 'skip_nil' arg in Omega#update_from

Specifies if nil attributes in source object should be copied
or ignored.

Use this to set nil attributes on the ship class (eg when
resetting mining / attacking / etc targets)
Slightly tweak examples/users.rb default locations