VE-473: add cart item selected styles.
VE-473: fix cart item image loading in Firefox; fix display bug of selected cart items when there's a scrollbar present.
VE-473: get rid of unused styles.
Merge pull request #1862 from Wikia/VE-473

VE-473: add cart item selected styles.
Adding placeholder text to search field
Merge pull request #1883 from Wikia/placeholder-text

Adding placeholder text to search field
Merge branch 've-sprint-5' into VE-533

Conflicts:
	extensions/VisualEditor/wikia/modules/ve/ui/styles/ve.ui.WikiaMediaInsertDialog.scss