[time zone] support for TZDatetime and TZTime data type Should be usable and cause no crash, though some stuff may still be refined (test value generation, display in views/forms...) Proprify some data structures dealing with yams base types along the way and adding warning when some were missing (eg Interval usually).

doc/book usr/share/doc/cubicweb-documentation
doc/html usr/share/doc/cubicweb-documentation
debian/cubicweb-doc usr/share/doc-base/cubicweb-doc