Fix planes that have more rows than columns

Fixes #574

The index calculations were not correct when rows outnumbered columns
for a plane. That was fixed, along with other changes to the class:

* Unused options (direction, texture coordinate rotation) and
constructors were removed. If someone wishes the plane to be rotated a
certain way, they can use the generic rotation methods.
* Auto-formatting was applied to clean up whitespace issues.