Update GeometryFactory.cs

The trim command result was not used.

The regular expression does not take into account WKT with a space between the identifier and the coordinates failing this case "MULTIPOLYGON (((...)))" only passes if the WKT has no space like this "MULTIPOLYGON(((...)))"
Merge pull request #2 from Siliconrob/patch-1

Update GeometryFactory.cs