JACOBIN-861 print values for BigInteger and BigDecimal

[texadactyl]

modified:   gfunction/javaIo/javaIoPrintStream.go
modified:   gfunction/javaMath/javaMathBigDecimal.go
modified:   gfunction/javaMath/javaMathBigDecimalFuncNtoZ.go
modified:   gfunction/javaMath/javaMathBigDecimalFuncNtoZ_test.go
modified:   gfunction/javaMath/javaMathBigDecimalHelpers.go
modified:   gfunction/javaMath/javaMathBigDecimal_50digits_test.go
modified:   gfunction/javaMath/javaMathBigInteger.go
modified:   gfunction/javaMath/javaMathBigInteger_test.go
modified:   object/string.go
modified:   types/constants.go

Fixed printing.
Installed the class names in the types package.

While we are at it, let's print and toString Thread and Thread$State.

• gfunction/javaLang/javaLangThread.go
• gfunction/javaLang/javaLangThread_members.go
• gfunction/javaLang/javaLangThreadState.go
• gfunction/javaLang/javaLangThread.go

And more unit tests, of course.