fix tests to work without a local configuration
simplify functional tests for Location
new game object creation

* add type specific <Model>.create class functions that take care of
  adding the newly created object to persistence, calling GSJS
  onCreate and some initialization/validation (depending on the type);
  new game objects should generally be created through these functions
* fail early in various error scenarios (no persistence data found for
  a requested TSID, creating an object with the TSID of an existing one)
always use locally mapped TSID for new locs/geos/groups

* when creating new "root" objects (locations/geos and groups), make
  sure their TSID is generated in such a way that the GS where they are
  created is also authoritative for them
* ignore first character for TSID/GS mapping (so locations and geos
  are always mapped to the same GS)
add GS RPC function for player creation
game object deletion

add a "del" function to all game object classes
functions for retrieving bag contents and adding items
itemstack splitting and merging

* add Item methods split and merge (functionality in line with the
  respective API functions)
* semi-related: modified gsjsBridge.init argument handling according to
  node conventions (callback argument last)
base function for adding items to player inventory
Merge pull request #11 from yelworc/item-mgmt

itemstack management