* WIP: Add stateless transducer tutorial. * Add more doc. * Minor fixes.
* Use new APIs with k2.RaggedTensor * Fix style issues. * Update the installation doc, saying it requires at least k2 v1.7 * Use k2 v1.7
* Begin to add documentation. * WIP: Add documentation. * Fix a typo. * Add more doc for the recipe yesno. * Add more doc for the yesno recipe.