add limit/offset support for graph

Hello @garbados, @housejester, 

Please review the following commits I made in branch 'sjkaliski-update-graph'.

b173ab2b993107e2d0337f900c6904fe920686f4 (2014-09-17 12:14:22 -0400)
add limit/offset support for graph

- [ ] The Server JS has been reviewed

R=@garbados
R=@housejester