Add transformation support for more block states

[avdstaaij]

There are still some orientation-related block states that the block transformation system could in principle support, but doesn't.

Known orientation-related block states that are currently not supported:

• type="bottom"/"top" (e.g. slabs).
  Note that slabs can also have type="double", and that type is used for all kinds of things!
• half="bottom"/"top" (e.g. stairs).
  Note that "half" is also used for other purposes, see e.g. doors.

Please mention any other missing block states in this issue!