nanochat

fix tokenization bug, there should be no space before first letter. sigh

add the SpellingBee task so that nanochat can count r in strawberry etc. along the way we had to add a bunch of new functionality, e.g. extend the calculator to support the count function of python. possibly the current TaskMixture uses way too many synthetic examples of SpellingBee because the eval gives us exactly 100% performance on spelling. We can tune this later to reclaim some wall clock time here I think

move the lr schedule args up in base_train so they are tunable in configurator

allow the tokenizer visualize_tokenization to also print the exact token id. you can never be paranoid enough