- Move hex for test txns into separate files in the testdata directory
- Convert tests to table-driven tests
- Make comments more consistent with the rest of the codebase
- Optimize the input sorting function to perform the hash equivalence
check before reversing the bytes so it can be avoided in that case
This converts the txsort code into a separate package and renames
'TxSort' and 'IsTxSorted' to 'Sort' an `IsSorted`, respectively.
It also adds a 'doc.go' and 'README.md' so it is consistent with the
other packages.