Extract mosart parameter using an outlet

[changliao1025]

To obtain a subset, an outlet id can be used to find all cells flowing to this outlet.
Once the cells are found, another function can be used to exact all the netcdf variables.

[changliao1025]

Mosart supports 2D and 1D, so both functions should consider the dimension differences.

If the input is 1D then output will be 1D.

Another function maybe used to convert 2D to 1D.