fix api/utils/config refs in core GSJS modules

* load global API/config/utils in the right order (utils needs valid
  references to api and config)
* also include GSJS "main" and "common" modules through a wrapper
  closure, because they need access to the global API, utils and config
  modules, too
add missing properties to player prototypes

* player prototypes need properties from items/item.js and
  items/bag.js, too
* unrelated: string substr&comparison should be faster than search
add GSJS helper functions to game object class

This is a workaround, but the "right" solution (see the docstrings)
will be much easier later, when the GSJS code is generated from DB
values and code templates again.
make unit tests fully independent of GSJS code
Merge pull request #17 from yelworc/gsjs-integration-pt2

GSJS integration, continued