update filter prototype
update mimic factory usage
update greyscale filter
update gaussian, bilateral and sobel gradient filter
fix resize canvas bug
Merge branch 'gh-pages' into refactor/filter-object-structure

Conflicts:
	assets/js/image-tools.js
	assets/js/image-tools.js.map
support shader program dependency
Merge branch 'gh-pages' into refactor/filter-object-structure

Conflicts:
	_assets/js/modules/itCommon/services/WebGL.js
update cartoon style shader