Modify biking speed.
Merge pull request #561 from joshmarcus/topic/biking_speed

Modify biking speed.
Increase biking speed.
Change license from GPL 3 to Apache 2.

This commit also updates version numbers and does a bit of cleanup in README.md.
Merge pull request #562 from joshmarcus/topic/change_license

Change license from GPL 3 to Apache 2.
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.