See <http://www.dessus.com/files/sqlnumeric.c> Implements a function ToBestType(x) which converts the value x passed as a parameter to its Best Type. - TEXT or BLOB parameter that "looks like a number" returns the number as Integer or Real as appropriate. - TEXT or BLOB parameter that is zero length returns NULL. - INTEGER or REAL parameter is converted to text and returns the same number in its most appropriate format (Integer or Real). - Everything else returns the parameter given.