#23 check argument order in all immutables

[Mike J. Bell]

The order of the arguments to create(...) in all
immutables should be reviewed, especially the ilm
(matrix) package. Specifically, positions and
dimensions should match in order, with major order
first and minor order second.

This means that for operations like *Segment, the
order should be:

row, column, height, width

Note that position is fully specified first, extent
last, with "y" first and "x" second (because matrices
are defined in row-major order).