Fix issues #181 and #191

[verseve]

Fixing issues #191 and #181.

Issue #181 is fixed by checking if the NetCDF variable var has dimension time in the ncread function. If this is the case, it is a cyclic parameter that is handled by the update_cyclic! function.

[visr]

The #191 fix looks good.

For the #181 fix, I see you check if time is in the dimnames. The read_dims function is made such that size 1 dimensions are allowed, so this would break size 1 time variables. Hence the error in #181 says "Only extra dimensions of length 1 are supported."

How does return nothing work for ncread? I'd think that this would crash later during initialization. One alternative approach would be to just read in the first or current timestep, which would then be updated by update_cyclic!. Perhaps we can make use of get_at to do this.

[verseve]

Yes, good point about the #181 fix. The approach is now to include dim time=1 in dim_sel of the ncread function (ce2fe91).