Add prescribed soil moisture streams as an option, and a few fixes

Add new prescribed moisture streams feature from Sean Swenson. This allows the user
to specify a steams file for soil moisture and use it in place of the model prognostically
determining soil moisture. To turn it on set use_soil_moisture_streams=T. You can also
set the filename to use with stream_fldfilename_soilm, and there are other _soilm namelist
items to control the years to run over. The file MUST be on the same grid as the model resolution.

Update 0.125x0.125 mapping and surfdata data, and fix hirespft data issues. Update cime
with SSP1-2.6 presaero data. So now can run the SSP1-2.6 CMIP6 future scenario.
Update rtm release branch to rtm1_0_69, which brings in a fix for cold starts.

Move mksurfdata changes from ctsm1.0.dev053 over, which fixes a rare soil color bug.