Add NMAKE version from Visual Studio 2012 Update 1

git-svn-id: http://svn.osgeo.org/geos/trunk@3784 5242fede-7e19-0410-aef8-94bd7d2200fb
Untabify

git-svn-id: http://svn.osgeo.org/geos/trunk@3785 5242fede-7e19-0410-aef8-94bd7d2200fb
Add algorithm/Centroid.obj

git-svn-id: http://svn.osgeo.org/geos/trunk@3786 5242fede-7e19-0410-aef8-94bd7d2200fb
Fix RobustLineIntersector handling of invalid intersection points (#622)

Adds new testcases. Many of them fail, probably due to the lack of
double double use, but one of them only fails with the old
RobustLineIntersector heuristic handling invalid intersection points

git-svn-id: http://svn.osgeo.org/geos/trunk@3787 5242fede-7e19-0410-aef8-94bd7d2200fb