create type decimal property min/max value

[Michael Brackx]

Hi,

There is an issue with createType.
Creating a type with a decimal property with a min/max value is not
(always) working.
The min & max value after parsing are null if the values are integers.
Using version 0.9.0.

JSONConverter.getDecimal() only accepts BigDecimal, but the value can also
be a BigInteger.

Michael