Adding new bathymetry file.

Signed-off-by: deepak <dpak.cherian@gmail.com>
Improved bathy_simple.m Now supports high and low, x and y.

Signed-off-by: deepak <dpak.cherian@gmail.com>
Made script order more modular / sane.

Signed-off-by: deepak <dpak.cherian@gmail.com>