fix: bb_slope fix: carea fix: icefilter

[rgknox]

This PR bundles 3 fixes that address:
#73
#69
#44

The fix to 73 is the only one that would be expected to have b4b regressions. I performed baseline simulation comparsisons between f1a14d6 and 18613d1, and tests confirmed b4b on all expected passes. One extra step was necessary, in that I needed to update the parameter file values of BB_slope to match what was previously hard coded (a value of 9). The current value in the default parameter file is 8, we can certaintly change this going forward. Not changing this now.

The other two fixes, #69 and #44 are not supposed to generate b4b results, and they don't. 1x1 brazil simulations were also run on eddi to make sure that the non-b4b changes continue to generate very similar projections of forest composition and structure, as well as flux variables. They did.

Fixes: #73, #69, #44

User interface changes?: no

Code review: Self

Test suite: lawrencium-lr3 intel, eddi (PC) gnu (visualizations)
Test baseline: 18613d1
Test namelist changes: none
Test answer changes: see above

Test summary:

DONE ERS_D_Ld5.f19_g16.ICLM45ED.lawrencium-lr3_intel.clm-edTest : (test finished, successful coupler log) 
     --- Test Functionality  ---:
    FAIL ERS_D_Ld5.f19_g16.ICLM45ED.lawrencium-lr3_intel.clm-edTest.clm2.h0.nc : test compare clm2.h0 (.base and .rest files) 
    FAIL ERS_D_Ld5.f19_g16.ICLM45ED.lawrencium-lr3_intel.clm-edTest.cpl.hi.nc : test compare cpl.hi (.base and .rest files) 
    FAIL ERS_D_Ld5.f19_g16.ICLM45ED.lawrencium-lr3_intel.clm-edTest : test functionality summary (ERS_test) 

DONE ERS_D_Ld5.f09_g16.ICLM45ED.lawrencium-lr3_intel.clm-edTest : (test finished, successful coupler log) 
     --- Test Functionality  ---:
    FAIL ERS_D_Ld5.f09_g16.ICLM45ED.lawrencium-lr3_intel.clm-edTest.clm2.h0.nc : test compare clm2.h0 (.base and .rest files) 
    FAIL ERS_D_Ld5.f09_g16.ICLM45ED.lawrencium-lr3_intel.clm-edTest.cpl.hi.nc : test compare cpl.hi (.base and .rest files) 
    FAIL ERS_D_Ld5.f09_g16.ICLM45ED.lawrencium-lr3_intel.clm-edTest : test functionality summary (ERS_test) 

[bandre-ucar]

testing on yellowstone