UI fixes..

1) Launch the bottom navigation pages inside the same tab
2) Display activity indicator while the data for the treemap is laoding.
3) Addded the TreMap icon provided by Tom inside the “In The Lab”
section.
4) RelationShip number styling update.
TreeMap Colors updated, Legend added to the TreeMap page
Merge branch 'Feature_Bottom_Links' into develop
Merge branch 'develop' of https://github.com/informaticslab/apollo into develop