shapes_in_area: Replace the topical variable with a more explicit name.

Signed-off-by: Shawn Laffan <shawnlaffan@gmail.com>
Rename $is_little_endian to $little_endian_sys.  It is a bit more self documenting that way.

Signed-off-by: Shawn Laffan <shawnlaffan@gmail.com>
Initial work implementing indexing for shapes.
Updates #11

Signed-off-by: Shawn Laffan <shawnlaffan@gmail.com>
Implement spatial index for shapes.
Updates #11

Signed-off-by: Shawn Laffan <shawnlaffan@gmail.com>
Only search the vertices for the bounds when we have more than one part.  Otherwise we can grab the cached values.
Test both polys using the spatial index.
(Updates #11)

Signed-off-by: Shawn Laffan <shawnlaffan@gmail.com>