- fixes and cleanups in grid helper
 * fixed grid shadowing issues when shadows are off
 * removed some unused code related to upVector
experimenting with lighting and materials, in order to get a good default
- updated three-editor and related elements:
 * transform-controls now dispatch specific events when there were actual transformations
done to the objects : translate & rotate handled for now (rotation code is quick ugly)
 * a primitive undo redo system is now implemented in the three-editor : works for translations
& rotations (see point above) a bit primitive but seems to work without issues so far
some very minor cleanup to grid-helper