M112 T133 - Adds WKT qmatcher to ds_discovery

M112 T133 - Adds qmatcher to ds_discovery

WKT matcher takes WKT string and optionally a buffer (in degrees). Circle is a point with radius size of buffer. Example {'wkt':'POINT(-70 40)', 'buffer':1.0} creates a circle centered on 40N,70W with a radius of 1.0 degrees.

Method (and buffer) works for all valid WKT shapes.

Needs https://github.com/ooici/pyon/pull/469 merged