Fix links in CESM documentation

[billsacks]

Some of the links are broken in the CESM documentation - in the quick start guide and maybe elsewhere. As just one example, the link for "create a case" points to http://esmci.github.io/cime/users_guide/create-a-case.html, which should point to the equivalent under: https://esmci.github.io/cime/versions/master/html/. That may be the issue for all of the broken links (i.e., http://esmci.github.io/cime/ should be replaced with http://esmci.github.io/cime/versions/master/html/ I think).