Prep for travel-script work (mimic "go2" functionality)
[Travel] scripting overhaul

* Introduce "nexus_movement_script_mixin.rb" -- scripts that include
  this mixin will navigate back to the "nexus" (if necessary) before
  branching out to another location
* Sort methods (by name) in all scripts
* Set "@args" during script instantiation rather than passing them into
  the "validate_args" and "run" implementations
* Use float values for sleep-durations throughout
* Remove base movement scripts (and create mixins from shared logic)
* Remove Threading from "base_script.rb" (pulling it up a layer into
  "script_helper.rb")

a#	modified:   app/scripts/dragonrealms/collect_script.rb