DDatabase.ident takes a Long

ident takes an entity id and find the keyword in the case that it is an entity with :db/ident
DDatabase.entity takes keywords and longs

one can look up a ident entity with its keyword, as well as a regular entity, by its id
implement Database.asOfT

returns the asOf point for the database
refactor and document DDatabase.entid
document the DDatabase methods
Merge pull request #21 from pellucidanalytics/topic/DDatabase

Expand and document DDatabase