Fix tag pattern.
Improve error handling.
Remove some debug.
More tags changes:
* Store a list of tags with each name
* Use a table with named fields rather than a list of bits
Implement actually jumping to the tag.
Implement :tn and :tp.
Implement :tsel <tag>
Implement ctrl-] and ctrl-t to find tags/pop stack.
Add support for :tsel without arguments (select from current tags).
Prune the top of the tag stack when re-pushing.