add csslint and new watch:dev task
server.js
add htmlhint and fixed html files
fixed csslint task
fixed ng-include
 add browsersync to admin and fixed ref #4270
fixed ref #4253
fixed ref #4270
Merge remote-tracking branch 'origin/master' into #4272-bec-IE-no-placeholders-shown

Conflicts:
	src/pages/admin/systemMessages/systemMessages-form.html
	src/pages/directiveTemplates/system/system-messages-list.html