Take a stab at adding Mean
Added Mean to zonal.summary ops
Added Tests for MinDouble and MaxDouble.  I noticed that SumDouble has a test, but these two were missing.
Removed println
Merge pull request #564 from ejc123/master

Mean for raster.op.zonal.summary and 2 missing tests
Need to handle count == 0 case.
Merge pull request #565 from ejc123/FixMean

Need to handle count == 0 case.
Noticed wrong variable comparison when looking over code.
Merge pull request #566 from ejc123/FixMean

Noticed wrong variable comparison when looking over code.
Process path fix for raster layer loading
Merge pull request #568 from lossyrob/fix/loadtileset

Process path fix for raster layer loading
Added ejc123 to contributors list.
Publish docs and sources in publish task
Merge pull request #570 from lossyrob/publishdocs

Publish docs and sources in publish task
Merge remote-tracking branch 'upstream/master' into 0.8.2
Merging current master