Nullability for RecordPtr data_franca Adapter
Fixed some minor bugs in data_franca
BelongsTo<T>::operator=
assign_attributes, create
String utility: split
Put POST params in Request.params
Include string support library in build
Monad interface for PrimaryKey
persistence: INSERT support
Better error message
Made tests compile again
Spelunker -> Spectator
Devirtualized a bit of the RecordType interface, and removed a number of now-unnecessary dynamic casts