Add options parameters to get/set column values via user defined functions.

Add support for data binding to column values which are functions -- in particular for Knockout JS -- and integrate this support into the editors.
Update addValue and loadValue to leverage args.grid

Add support for data binding to column values which are functions -- in particular for Knockout JS -- and integrate this support into the editors.
Merge remote-tracking branch 'remotes/chadPrice/patch-1' into v2.0-merged

Conflicts:
	slick.grid.js
Merge remote-tracking branch 'remotes/chadPrice/patch-2' into v2.0-merged

Conflicts:
	slick.editors.js
Merge branch 'master' into v2.0-merged
Merge branch 'master' into v2.0-merged

Conflicts:
	slick.grid.js
Fix #864 - Implement a 'destroy' method on Slick.ColumnPicker.
Merge branch 'original-master'
update submodules
Merge remote-tracking branch 'remotes/jlerasmus/v2.0-merged' - provide both getter and setter via columnDef and metadata structures

Conflicts:
	slick.editors.js
	slick.grid.js
ensure all editors use the slickgrid-provided value getter and setter
gitignore npm install directories etc.