* Fix typos pointed out in review by @ttmc
* Reword description of an input in the transaction schema
* Re-add removed comment in transaction model
* Fix small typos in some comments in the transaction model
* Add trailling commas to a multiline dict in the transaction model tests
* Fix small things with server docs changes
* Add description of public keys' association with conditions in transaction concept docs
* Reword description of Transaction.create's and args
* Rename output_uri to output_condition_uri
* Fix hardcoded class name vs. self.__class__
* Rename instances of 'out' with 'output'
* Rename instances of and with to avoid name clash with built-in
* Remove unnecessary renaming of cryptoconditions.Fulfillment import in transaction model
* Remove instances of in transaction model
* Remove usages of fulfillment in cases where input makes more sense
* Reword docstrings for init methods in transaction models
* Rename usages of condition where output is now a better fit
* Add descriptions to TransactionLink's txid and idx in schema
* Minor correction to output idx description in transaction yaml
