Update David support - visual style

[risserlin]

Since David has recently been updated and many people use David as their enrichment of choice need to update it.

David results should have the visual style label set to GS_NAME as opposed to GS_Descr. (Description means nothing in DAVID results). Alternately when reading in DAVID data set description to the same as the name so don't have to have a special style for DAVID.