add syllabication check

[eroux]

we're starting to have usable syllabication patterns on hyphen-la and I think it would be quite useful to integrate a checker against these patterns in Gregobase.

This could be done in two ways:

• integrate the python script I've done for Gregorio (see this PR)
• implement a small gabc parser in php (copied from the python script) and hyphenate directly in php (see this example)

This type of checking has proven very useful on a few big projects I've been involved in, so I think it could benefit users a lot