slicetype: avoid implicit integer conversions, fix MSVC warning

intraCost is an int array, so there was no purpose to downcasting to uint16_t
cli: expose param.bRepeatHeaders to the CLI, reorder help for more clarity
rest: fix indent of min-crf
TComPic: nits
reduce code size on intra_pred_ang8_*
rdcost: fix comments for lambda fix8 variables, refs b77ca886ef3b
reduce malloc call to avoid fragment and overhead