Note on obstype terminology for quantity

[hkershaw-brown]

There are places in the code where obstype is used, but the variable/argument is referring to qty

We've updated this in the template model, and when we refactor model_mods, but there is still a lot of 'obstype' hanging around in model_mods and fwd ops. Particularly for people using the QCEFF and debugging their runs, the loose naming type (for qty) adds an unneeded overhead to reading the code.

[hkershaw-brown]

A big one is qty files in the directory:
DART/assimilation_code/modules/observations
qty files in the directory named 'observations'.

[hkershaw-brown]

DEFAULT_obs_def_mod.F90

DART/observations/forward_operators/DEFAULT_obs_def_mod.F90

Lines 573 to 586 in c5600dc

	! Compute the forward operator. In spite of the variable name,
	! obs_kind_ind is in fact a 'type' index number. use the function
	! get_quantity_for_type_of_obs from the obs_kind_mod if you want to map
	! from a specific type to a generic kind. the third argument of
	! a call to the 'interpolate()' function must be a kind index and
	! not a type. normally the preprocess program does this for you.
	select case(obs_kind_ind)
	! arguments available to an obs_def forward operator code are:
	! state_handle -- to access the state vector
	! ens_size -- the number of ensemble members to do at once (between 1 and ens_size)
	! copy_indices -- the indicies the ensemble members (between 1 and ens_size)
	! location -- observation location
	! obs_kind_ind -- the index of the observation specific type

obs_kind_ind is type.