Updated sheet-lib.js to return empty string when we are trying to get empty cell. GFI: Added test that check next behaviour: After call prepare - all previous data was deleted.
Added possibility to test, Multiple content folders at once.
Added test for accessing wrong range in sheet-lib.js Restored not skipped test.
Updated google-docs-model.js to support empty sheets.
Made same google-docs-model.js applyable for Google and Node.
Skipped broken test.
Added path generation target to Makefile.