Readme updates

[tpietruszka]

Got here through the Mogrifier paper. Great read, and the 'case for small scale' is really refreshing. I am surprised to see no activity here.

Updated a few broken links in READMEs

Also, installing tensorflow-probability-gpu=1.15 did not work (package not found), but I have found some claims that it is now sufficient to install tensorflow-probability. Training seems to work (at least for a few "turns"), without the -gpu.

[melisgl]

Thank you. I'll merge this as soon as I figure out how to include incorporate the changes correctly into the internal codebase from which this repo is exported.

[jkkummerfeld]

Not sure what I did differently, but I found the code didn't work with the latest version of tensorflow-probability. Instead I solved this issue with he following:

    pip install --upgrade --user "tensorflow<2" "tensorflow_probability<0.9"
    pip install dm-sonnet==1.36