Update REFCASEs to work with new fsurdat files in release-clm5.0.20

REFCASES needed to be interpolated to work with new fsurdat files in release-clm5.0.20. This is the start of that process.

User interface changes?: No
Fixes: #107
Testing:
system tests:
SMS_Ln1.f09_g17.B1850.cheyenne_intel.allactive-defaultio.20190314_115153_xlpcd1
SMS_Ln1.f09_g17.B1PCTcmip6.cheyenne_intel.allactive-defaultio_min.20190314_115153_xlpcd1

Update CAM version, update REFCASES to be interpolated for CLM, use interp for cases without CMIP6DECK option

Update more REFCASEs, and remove all of the CLM_NAMELIST_OPTS which set use_init_interp=T and in some cases the interp_method, the updated REFCASES should already take care of this

testing: passed following tests
ERS.f09_g17.B1850_BPRP.cheyenne_intel.allactive-defaultio
ERS.f09_g17.B1850_BPRPcmip6.cheyenne_intel.allactive-defaultio

visual inspection of env_run.xml and namelists in above tests
to confirm BPRP settings

Add SSP5-8.5 compsets and test

Add BSSP585, BSSP585cmip6 and a couple tests for it. Remove some of the RCP compsets and tests. This branch was made relative to cesm2.1.1-rc.01.

User interface changes?: Yes
New compsets for CMIP% SSP5-8.5 scenario

Fixes: #104 #97

#104 -- remove CMIP5 RCP's
#97 -- future scenario names need to change
Testing:
system testing: SMS_D_Ld1.f09_g17_gl4.BSSP585cmip6.cheyenne_intel.allactive-defaultio PASS

Fix some issues, get the SSP compsets all working, consolidate how they are handled so there's not more than one way to do it, make sure only the WACCM SSP534 compset uses 2040 start, also make sure matching does not require CMIP6 settings, but is more general like the other BHIST compsets

    modified:   Externals.cfg
    modified:   cime_config/config_compsets.xml

Correct WACCM SSP compset long names.

Remove the "-" and "." characters from compset long names.

Testing: bwaccm

        modified:   Externals.cfg
        modified:   cime_config/config_compsets.xml

Add a pelayout for bluewaters f09_g17 B
User interface changes?: No

Fixes:
Testing:
unit tests:
system tests: PFS.f09_g17.BHIST.bluewaters_intel
manual testing:

    modified:   Externals.cfg
    modified:   cime_config/config_compsets.xml
    modified:   cime_config/testlist_allactive.xml

Add compsets:
BWSSP245cmip6
BWSSP370cmip6

Testing: bwaccm

        modified:   Externals.cfg
        modified:   cime_config/config_compsets.xml
        modified:   cime_config/testlist_allactive.xml

This brings over all changes to the documentation (i.e., the doc
directory) that were on master but not on this cesm2.1 release branch.

Related to https://github.com/ESMCI/manage_externals/issues/115

Use CASENAME rather than CASEROOT, and rework the documentation of that
option. This is to remain consistent with changes in
https://github.com/ESMCI/cime/pull/2693

A significant change is clarifying the use of $VAR. I removed uses of
$VAR as things the user should fill in, because this seems confusing to
new users, who think this means that VAR should be a shell environment
variable. I have also repeated the description of the use of $VAR near
the top of the quickstart page, as Gunter suggested.

I have also added a bit of clarification about CASEROOT, as I did in the
cime documentation in https://github.com/ESMCI/cime/pull/2693.

I have also explicitly pointed out that most output won't appear under
the case directory, since this was confusing to Gunter.

This way, the user will be able to see history files. This was suggested
by Gunter Leguy.

Also some other minor edits to the quickstart.

```
    modified:   cime_config/config_compsets.xml
    modified:   cime_config/testlist_allactive.xml
```


Add the SSP compsets for WACCM

User interface changes?: no

Fixes: [Github issue #s] And brief description of each issue.

Testing:

system tests: bwaccm

        modified:   cime_config/config_compsets.xml
        modified:   cime_config/testlist_allactive.xml