dem-stitcher v2.1.0

Changed

• dem_sticher.sticher.stitch_dem no longer returns the raster profile and data
  array and instead writes the output stitched DEM to a file as specified by the
  new filepath argument.

Fixed

• Pixel shifts sometimes seen in stitched output DEMs (see #18)
• Package data is again included with python wheel distributions,
  which was missing in v2.0.1
• Properly handle no-data values and geoid bounds.