Log of breaking changes in 0.2 beta

[jbloom]

see:

[Breaking Change] Hail 0.2 removed KinshipMatrix, linear_mixed_regression

(Update: Hail 0.2 has a function linear_mixed_regression_rows which most closely implements the old linear_mixed_regression function) The KinshipMatrix class is gone. Instead, realized_relationship_matrix and genetic_relatedness_matrix both return a BlockMatrix with improved performance. The gcta_grm and gcta_grm_bin on KinshipMatrix are therefore gone as well. BlockMatrix supports export, as well as and conversion to_numpy for further processing if small enough (less than 46k samples, assuming…