reworked how y-axis labels are drawn so they don't get overwritten by the...

reworked how y-axis labels are drawn so they don't get overwritten by the actual graph.  Also some other bugfixes that fell out from there.

Ignore-this: 2eed13abbe1d6f828a664f2239bcb38

darcs-hash:20090825040823-ac9f3-cf7156fd0493900088419eb95123d0c88d111d92.gz