Feature/vic 4.1.2.wetcarb.new

This branch contains two new features slated for release in 4.2: carbon cycling (issue #13) and lake bottom heat flux (issue #16).

However, there is one more feature (distributed water table) that is also in this feature branch.  It is the final commit.  So, if you want to pull in the other two features (carbon cycling and lake bottom heat flux), you will want to merge from the penultimate commit.

Sorry about this - I didn't know how to submit the pull request for the penultimate commit (and I needed to make that commit to make this branch available to others in the form that they need).