param: enforce a minimum picture size

Do not allow the user to configure a picture smaller than at least one CTU
param: nit reorder of RC mode checks to avoid uncrustify problems

uncrustify was seeing FOO(bar < x || bar > y) and assuming this was a template
instantiation and changing it to FOO(bar<x || bar> y).  Reordering the two
comparisons avoids this problem
rest: nit
TEncEntropy: nit
cli: add missing --no-dither option to getopt list