Bias-correct TEOTIL2 output prior to 2013

[JamesSample]

TEOTIL3 simulations begin in 2013. To create plots for TOTN and TOTP for the whole period of interest (1990 to present), we need to use TEOTIL2 results, bias-corrected to match TEOTIL3 for the period of overlap. I will do this in a simple way using the "delta-change" method (essentially just the difference in source-specific means for 2013-22).