new material types

[eroux]

The cudl data contains some data about material that would be interesting to record:

• nep_multi_layered_black_paper (nep == Nepalese probably)
• corypha_palm_leaf (that they differentiate from palm_leaf
• mixed
• black_paper (note that we could have some properties on materials)

I'm thinking we could also add Tibetan rice paper while we're in this kind of additions

[eroux]

I added some individuals for the CUDL import