Rename sphelper/main.go
sphelper/doc: move more logic to package
"Bugfix" EAN13 < 13 digits and show text = yes

There have to be 13 digits in order to show the text
beneath the bars. We switch off text if there are less 
than 13 digits.

This is not a proper fix, but a works well enough for now
workaround (a crash is evil!)

Fixes #17
Bugfix: escape string to be pattern safe

CSS classes can now have a "-" inside the name. The dash
was interpreted as a lua pattern...
Add more CSS support (Tablerule)