prevent tick labels from overlapping

[cpankow]

Affected: 1dcdfs.py, 2dcdfs.py

Because the subplots in the current plots are all very tightly bound together, the tick labels (particularly, the first and last) tend to overlap. I've fixed this for most cases. However, this is a bit of a hack since I've had to call out the specific tick label by index (using -1 doesn't work because the number of ticks is only determined at render-time) and it doesn't work at all for the LogFormatter. Even attempting to override it with a ScalarFormatter(from here) seems to undo the exponential formatting and ignore what I ask it to do.

Anyone wanna take a stab at this? @eachase? It has to be fixed before we submit to the journal.

Thanks!