Caching recent searches for autocomplete

Added new panel at autocomplete with recent searches, minlength for
autocomplete changed to 0, but will do request to database only if 2+
chars in string. also did little changes at jquery.tagsinput
if( value ) {}
will evaluate to true if value is not:
null
undefined
NaN
empty string ("")
0
false

example: http://jsfiddle.net/Hotspur/f9zqecyj/