Expanded README.md, bug fixes

FIXED:
- {@file.textlet} tags now properly handle customizers
- {@file.textlet} tags now properly search the documented directories
when the file's path is relative.

ADDED:
- Named debugger "zzFileTextProcessor.obtainingfile"

DOCUMENTATION:
- Beginning examples from overview-summary.html are now in README.md.
But it is just manually placed there. Will eventually automatically get
them from the overview-summary file.