Enable more linters, address the issues and do a major naming refactor
to use golang lower camelCase identifiers for types, functions, methods
and variable names.
Also:
* Clean up inline generation so it doesn't rely on temporary variables.
* Remove unused functions generated by inline.pl.
* (#257) Change Walk/Visit to follow an explicit Enter/Exit pattern
* (#257) Convert walk example into test.
* (#257) restore walk/visitor example
* (#257) Fix godoc comment in the Visitor interface
... typo referred to `End` method instead of `Exit`
