shebanq: Working with data versions etcbc-4,4b

The shebanq site is stable. It works with data versions 4 and 4b. Version 4b is frozen. The first new data version is 4s.

The following tools are in place:

• parallel (providing the crossref notes)
• phono (providing the phonetic transcription)
• valence (providing the valence notes that implement the flowchart of verbal valence, in development)
• trees (an export of all sentences to tree structures)
• verbsystems (Gino Kalkman's supporting notebooks to his Ph.D. thesis)
• shebanq (the dataflow from etcbc data plus extras to the website shebanq)

There might still be minor bugs to be fixed.