Removed buffer parameters from interpolate
Removed buffer parameters from interpolate

The high level function 'interpolate' automatically creates bounds for
data, filling in grids with null if they have too few neighbors, etc.
Buffer is therefore pointless in this function and should be removed.
It still exists in the lower level functions if someone wants to use it
there.

ahaberlie/MetPy,dopplershift/MetPy,jrleeman/MetPy,Unidata/MetPy,ahaberlie/MetPy,dopplershift/MetPy,ShawnMurd/MetPy,Unidata/MetPy,jrleeman/MetPy,ahill818/MetPy