Add support for using HYCOM data (which doesn't get put into a data.variable.data array but instead in a simple data.variable array).
Make a minor change to the vertical interpolation to support HYCOM data.

Since the HYCOM data are a fixed water depths rather than sigma levels,
we need to create an index of the values which are below the water depth
at this node and then eliminate them from the linear interpolation.
Fortunately this is relatively easy to do (so long as we create an
appropriate depth array) in such a manner as won't affect the POLCOMS
vertical interpolation.
Fix the net heat flux variable name and flip the latitude array to
ensure the data are properly referenced in FVCOM.

It appears that for version 3.1.6 (official) of FVCOM, the expected
variable name in the WRF format netCDF file is not Net_heat (as Dima's
file has) but is instead net_heat_flux (as the rest of FVCOM uses).

The latitude variable needs to be flipped in the same way as the data
arrays, or, none need to be flipped. The downside to the latter is that
although FVCOM will read them correctly, viewing them with something
like ncview will render them upsidedown. Not a massive pain, but enough
of a nuisance for me when I was debugging this that it was easier to
flip everything.
Minor changes to the debugging figure properties
Fix the help to actually reflect the function.
New function to interpolate the fixed level HYCOM data onto the FVCOM
horizontal and vertical grid.

Interpolate HYCOM's odd fixed level data onto the FVCOM model grid to
use as a warm start for FVCOM. During the coding of this function, it
became apparent that the interp_POLCOMS2FVCOM.m function is pretty
poorly written from a variable number of inputs perspective. This
function can probably be used as a template to improve the POLCOMS
version, should it be necessary.
Remove unneeded code.