Subscripted Reference for Structures

Applies indexing to the fields in a structure in much the same way as subsref.m works with matricies, vectors, etc. The indexing is only applied to fields with n columns (or rows).

Example call: S = subsref_struct(S,i,n,rc)

Applies the indexing given in i, to the fields in S that have the
matching number of columns (n). Given a 4th input will apply the indexing to the rows (1) or columns (2), defaults to columns.

Example:
Create a structure with mixed fields, array and structure
d.lon = ones(5,1)*[1:10];
d.lat = ones(5,1)*[1:10];
d.time = 1:10;
d.strct = d;

Change the column indexing
S = subsref_struct(d,2:5,size(d.lon,2),2)

Change the row indexing
S = subsref_struct(d,1:2,size(d.lon,1),1)