graphBoundaries feature issues

[TerryHodgson]

1. When the boundaries are not whole numbers, there is no way to use the xsl to truncate the long doubles.
2. One might want to consider adding new features: xBoundaries and yBoundaries, or xBoundLeft, xBoundRight, yBoundBottom, yBoundTop.

[TerryHodgson]

Doing #2. would also support more faithful implementation of the altformatsolutions template. It would also lend more flexibility in formulating new descriptions.