currentUser: cache cluster list in localstorage
added preview for cluster item
fixed ng-src for images; load large items for cluster gallery
added basic paging for cluster gallery
#unit test: fix 4 unit testing issue. logout test is still failed
fixed tests for login/logout
added new libs: jQuery2, rxjs
gallery: load on scroll initial version
gallery: load on scroll and resize using RxJS
set gallery page size to 12 items