Merge tag 'ctsm1.0.dev089' into lunadaylbugs

Bring documentation source to master

1. Bring documentation source to master: Pulls in the source from
   https://github.com/escomp/ctsm-docs. This is important so that
   documentation can remain in sync with changes in the model
   code. Images are stored here using git-lfs (Git Large File
   Storage). I also made some minor fixes to get the pdf build of the
   tech note working.

2. Use a different documentation theme that supports a version dropdown
   menu, and add the code needed to support this versioning on the
   documentation web pages. At a high level, the way the versioned
   documentation works is to have separate subdirectories in the
   gh-pages branch of the ctsm-docs repository for each version of the
   documentation we want to support. There is then a bit of JavaScript
   code which uses a json file in the gh-pages branch to determine which
   versions exist and how these should be named in the dropdown
   menu. Most of these changes were borrowed from ESMCI/cime#3439, which
   in turn borrowed from ESCOMP/CISM-wrapper#23, which in turn was a
   slight modification of an implementation provided by @mnlevy1981 for
   the MARBL documentation, which in turn borrowed from an
   implementation put together by Unidata (credit where credit is due).

   I am not aware of out-of-the-box support for a version pull-down in
   out-of-the-box sphinx themes (though the last time I looked was in
   Fall, 2018, so there may be something available now). However,
   support for a version dropdown exists in an open PR in the sphinx
   readthedocs theme repository: readthedocs/sphinx_rtd_theme#438. I
   have pushed this branch to a new repository in ESMCI
   (https://github.com/ESMCI/sphinx_rtd_theme) to facilitate long-term
   maintenance of this branch in case it disappears from the official
   sphinx_rtd_theme repository. I have also cherry-picked a commit onto
   that branch, which is needed to fix search functionality in sphinx1.8
   (from readthedocs/sphinx_rtd_theme#672) (which is another reason for
   maintaining our own copy of this branch). The branch in this
   repository is now named version-dropdown-with-fixes (branching off of
   the version-dropdown branch in the sphinx_rtd_theme repository). In
   the long-term, I am a little concerned about using this theme that
   isn't showing any signs of being merged to the main branch of the
   readthedocs theme, but this has been working for us in other projects
   for the last 2 years, so I feel this is a reasonable approach in the
   short-medium term.

The new process for building the documentation is given here:
https://github.com/ESCOMP/CTSM/wiki/Directions-for-editing-CLM-documentation-on-github-and-sphinx

Resolves ESCOMP#239

.gitattributes

@@ -0,0 +1,6 @@
+*.svg filter=lfs diff=lfs merge=lfs -text
+*.png filter=lfs diff=lfs merge=lfs -text
+*.jpg filter=lfs diff=lfs merge=lfs -text
+*.jpeg filter=lfs diff=lfs merge=lfs -text
+*.gif filter=lfs diff=lfs merge=lfs -text
+*.pdf filter=lfs diff=lfs merge=lfs -text

.lfsconfig

@@ -0,0 +1,2 @@
+[lfs]
+        fetchexclude = *

bld/namelist_files/namelist_defaults_ctsm.xml

@@ -372,8 +372,8 @@ attributes from the config_cache.xml file (with keys converted to upper-case).
 <!-- The default filenames are given relative to the root directory
      for the CLM2 data in the CESM distribution -->
 <!-- Plant function types (relative to {csmdata}) -->
-<paramfile phys="clm5_0">lnd/clm2/paramdata/clm5_params.c190829.nc</paramfile>
-<paramfile phys="clm4_5">lnd/clm2/paramdata/clm_params.c190829.nc</paramfile>
+<paramfile phys="clm5_0">lnd/clm2/paramdata/clm5_params.c200402.nc</paramfile>
+<paramfile phys="clm4_5">lnd/clm2/paramdata/clm_params.c200402.nc</paramfile>
 
 <!-- ================================================================== -->
 <!-- FATES default parameter file                                       -->