Add 2D routines

[NiklasPhabian]

STAREMaster and pystare can accept 2D arrays of lat/lon to lookup SIDs.

See, e.g. SpatioTemporal/pystare#6

They take advantage of the non-flattened form to adjust the level to the distance to the neighbors.

This should really be a STARE, not a STAREMaster AND pystare functionality

[michaelleerilee]

Regarding adding to STARE: we'll need to add a 'direction' parameter that defines which array elements to use to determine neighbor/resolution level. Perhaps the following. idir == 0: Check all neighbors to set levelidir > 0  : Check along dimension idir I guess it's possible one might wish to check along more than one dimension, in which case a kernel  would be more appropriate. E.g. source_array[i1,i2,...,iN] = <data> kernel[i1..iN] a number indicating how many neighboring elements to consider in each dimension