prevent Autocomplete from causing errors when quickly opening / closing dialogs
cache autocomplete results in sessionStorage for faster results
added fallback for browsers w/o sessionStorage
clear sessionStorage when logged out, so the Autocomplete cache doesn't remain stored in the browser
indicate preloading state of Autocomplete, to give some feedback in case of slow connections
Merge pull request #50 from Crabgrass/feature/4284-autocomplete-improvements

autocomplete improvements