added definitions for missing ngGrid interfaces and created tests for them
Decomposed some of the classes so that the constructors worked properly

added definitions for missing ngGrid interfaces and created tests for them
Merge branch 'ng-grid' of https://github.com/rolandzwaga/DefinitelyTyped into ng-grid

Conflicts:
	ng-grid/ng-grid-tests.ts
	ng-grid/ng-grid.d.ts

Fixed some double var declarations in test
Merge pull request #2139 from rolandzwaga/ng-grid

Added definitions for remaining ng-grid interfaces