Traversal methods are updated to use the new Walk module such that
sequences with nested Inline (or Block) elements are traversed in the
order in which they appear in the linearized document.
Fixes: #5667
This makes use of tasty-lua, a package to write tests in Lua
and integrate the results into Tasty output. Test output becomes
more informative: individual tests and test groups become visible
in test output. Failures are reported with helpful error messages.
