enforce position relative on phylo tree container
Merge branch 'master' of github.com:kltm/bbop-js
Merge branch 'master' of github.com:kltm/bbop-js
Merge branch 'master' of github.com:kltm/bbop-js
fix tree width calculation
switch to gridlines rather than having DOM elements for each grid cell

reduces the number of matrix DOM elements from O(width * height)
to O(width + height + filled cells)
Merge pull request #22 from skinner/master

matrix grid lines, hopefully fix embedding