New methods:
- Expr.getNumeralDouble(): retrieve any numeral as a double
- IntNum.getUint(): extract numeral as unsigned 32-bit value
- IntNum.getUint64(): extract numeral as unsigned 64-bit value
- RatNum.getSmall(): numerator/denominator as int64 pair
- RatNum.getRationalInt64(): numerator/denominator (returns null on overflow)
Each is a thin wrapper around the existing Native binding.
Added examples to JavaExample.java covering all new methods.
A lot of existing code in Java bindings catches exceptions just to
silence them later.
This is:
a) Unnecessary: it is OK for a function to throw a RuntimeException
without declaring it.
b) Highly unidiomatic and not recommended by Java experts (see Effective
Java and others)
c) Confusing as has the potential to hide the existing bugs and have
them resurface at the most inconvenient/unexpected moment.
