[HSQLDB] HSQLDictionary wrongly maps double to NUMERIC without precision

Right now we create a NUMERIC field without any precision digits for double fields. This results in zero decimal fractions, which is clearly wrong.

We should rather use DOUBLE SQL type, which is a 64bit 'aprox' type. If someone wants to use a fixed prec+scale then use BigDecimal which will be mapped as DECIMAL(n,m)