fix axes

didn't have to change much, just a couple small problems:
* ce29b3c axes needed extra room to be displayed, as per [d3 margin conventions](http://bl.ocks.org/mbostock/3019563)
* 9979488 the x scale was weird/broken
* 9979488 the label fonts were white

the last commit 9d47ede has no effect, just simplifies code and makes the treatment of x and y more consistent