Add mlkit support and bump to 1.3.0

We might as well add MLkit support given its glorious resurrection :)

I also got rid of the dependency on the SMLNJ Util library, given that we were only using it for sorting (it's something of an impediment for PolyML support too).

FYI @robsimmons, @melsman  - I'll likely merge this as soon as someone agrees.