Flot plugin to display angled X-axis tick labels.
https://github.com/markrcote/flot-tickrotor

Requires flot 0.7 or higher and a browser supporting <canvas>.

To activate, just set xaxis.rotateTicks to an angle in degrees.  Labels are
rotated clockwise, so if you want the labels to angle up and to the right
(/) you need to provide an angle > 90.  The text will be flipped so that it
is still right-side-up.

Angles greater than or equal to 180 are ignored.

If set, xaxis.rotateTicksFont is used for the ticks font.  Otherwise, the
CSS font property for the tickLabel class is used.  If neither is set, the
default is 'smaller sans-serif'.

The graph is resized so that all labels can be displayed properly.
- NOTE: currently this only works with label angle > 90 degrees.

If you are using this with flot-axislabels, include flot-tickrotor *before*
flot-axislabels, since the former completely redefines the X-axis
labelHeight, and the latter only modifies it.

TODO
----

- Fix plot resizing with long labels when angle < 90 degrees.  It seems to
  require a y2axis at the moment and fails if one isn't defined.