This invention relates to compounds of Formula (I)






and enantiomers thereof, and to pharmaceutically acceptable salts of Formula (I) and said enantiomers, wherein R1, R2 and R3 are as defined herein. The invention further relates to pharmaceutical compositions comprising such compounds and salts, and to methods and uses of such compounds, salts and compositions for the treatment of abnormal cell growth, including cancer, in a subject in need thereof.