Sentiment Analysis added

Sentiment Analysis added for twitter.
created WCVDocument4Sentiment.
changed Word object to store sentiment value.
Added Orange-Grey-Blue sentiment Color Scheme.
Moved createLoadingBox to AppUtil. created Class : WordCloudGenerator
contains common methods used by WordCloudServiceImpl &
WordCloudDetailServiceImpl.
Set the minimum word length to 3.
added SentimentReader Interface. so We analysis the text based on
entire tweet instead of each sentence within each tweet (This can be
changed if needed).
DocumentExtractor now returns the DocumentReader instead of text.
Because reader type will be determined later in word cloud generation
process.