Streamline Api and document functions

[jamil7]

• The Postgres function to add pooling settings does the same thing as the one from a raw Npgsql configuration string, while not adding any sort of convenience
• AsyncResultHandler returns only the exception message as a string in the error case. It would be nice if it returns the whole exception object instead
• The ReadRaw with prefetch functions take a redundant boolean as a parameter, this will be removed