baharmon/r.earthworks: r.earthworks 1.0.0

This is the first release of r.earthworks - a tool for computational terrain modeling. It uses cut and fill operations to excavate and build new landforms. It can be used to model topographic features such as hills, pits, ridges, valleys, levees, roads, lakes, mines, and breaches. Features include cut-fill operations, absolute or relative mode, linear or exponential slope functions, flats around local minima and maxima, and volumetric change calculations. This release includes unit tests for cut, fill, and cut-fill operations. This version has been merged into GRASS addons.