[README] Fix a mistake in an example

Typo

Update tests for ./examples/11-utm.tula

Add description for examples/11-utm.tula

Remove the Development disclaimer

Implement customizable head position

Factor out struct Tape

Add a section about testing

Remove obsolete *.expect files

Replace current testing framework with rere

Update TODO

Replace normalization with enumeration

Factor struct NormExpr into a function

Remove duplication of user reporting of sanity checks at runtime

Update TODO