filter out retweet, follow
switch to frlayout2
Merge branch 'master' into soln

Conflicts:
	src/SocialNetwork.java
revert to frlayout
Merge branch 'master' into soln
lower threshold
add support for node categories and colors
Merge branch 'master' into soln

Conflicts:
	src/SocialNetwork.java
add weak component soln
use stack to avoid recursion limit