CMS-3391 Image Picker - Add square boxes around images

* Added box with 1px light-grey border and white bg around images
* dropped the grey border, when zooming image
* added the standard "glow" to the image, when image is zoomed
* dropped image name on mouse over when image is zoomed
Merge branch 'master' of github.com:enonic/wem-ce into CMS-3391

Conflicts:
	modules/wem-webapp/src/main/webapp/admin/common/styles/api/form/inputtype/image-selector.less
Merge pull request #717 from enonic/CMS-3391

CMS-3391 Image Picker - Add square boxes around images