tokenization: low-porosity

[odanoburu]

low-porosity is not in WN, but both low and porosity are. we could add it (as there's high-energy, low-tension), but if we use the conventionality and compositionality criteria for MWEs, I don't think it fits. how to handle it in the interface? (if we had low porosity we'd be annotating both tokens)

or should we just handle this at the pre-processing level? (it's more consistent, at least) how?