days.kyro gone for some reasom
added cleanPersistentData
fixed getTemporalHistogram's implementation
refactored the date formatter static final field
fixed a bug in Hashtag.equals()
hashtag unit test
hashtaginfo unit test
no more date trimming
documented a empty block to remove warning
removes unnecessary imports
mixed Dict withhashtags into dictWithHistograms (implements
GenericMapStreamer)
makes the singleton a private final fields
added a test for popularity, at the moment the test found a bug no
fixed: 

for each retweet we need to increase the popularity of the ORIGINAL
TWEET's hashtags, and not the hashtags of the current retweet,

actually, retweet's hashtags does not count (according to the piazza) at
all.
example: C is a retweet of B and B is a retweet of A
each has a hashtag with it's name

A's popularity is 2(has 2 retweets)
B's and C's popularity are 0!! (not counting retweet's hashtags)
fixed the bug in popularity
reordered test
extends test, atm has some bugs to fix