created new branch for displaying frequent terms and with tweet filtering function.
modified layout. showed term count.
new branch. remove frequent terms. modify heatmap-leaflet draw function to re-use existing canvas of tile in drawing debug info, instead of creating new one that causes blurred text.
extracted frequent terms and showed up on heatmap.
show tweets when zoom in to certain level.
adjust font size. use regex tokenizing.
add regex patterns.
add option for choosing certain type tweets. add tweet label in received messages.
show more terms when in topic-specific map.
adjust layout. add title, desc, copyright.
add twitter sentiment.
upgrade Leaflet to version 0.7.3. modify some server parameters.
Merge pull request #1 from viirya/group_terms

merge group_terms branch