Adding src/physics/cam/ files necessary for clubb gustiness.

also adding the CMEPS files necessary for these changes, although
they really should be in the separate ESCOMP/CMEPS external.
currently they are a top-level directory CMEPS_mods.

Author: bstephens82

CMEPS_mods/README

@@ -0,0 +1,9 @@
+Put source mods for the drv library in this directory.
+
+WARNING: SourceMods are not kept under version control, and can easily
+become out of date if changes are made to the source code on which they
+are based. We only recommend using SourceMods for small, short-term
+changes that just apply to one or two cases. For larger or longer-term
+changes, including gradual, incremental changes towards a final
+solution, we highly recommend making changes in the main source tree,
+leveraging version control (git or svn).