IsValidOp unit test<1> failed on windows msvc2008 build environment

[sanak]

FINITE(DoubleNotANumber) doesn't return 0 at IsValidOp::isValid.

I had make patch for this problem.

the fixed points are as follows.
1) change DoubleNotANumber value from 1.7e-308 to numeric_limits<double>::quiet_NaN().
1) change DoubleInfinity value from 1.7e+308 to numeric_limits<double>::infinity().
2) add DoubleMax definition (use numeric_limits<double>::max()), because JTS Double.MAX_VALUE and Double.POSITIVE_INFINITY are same in GEOS (I think that this is a bug).
3) add Coordinate::isNull for get equality of NaN value.

I think that xnix environment have same problem (platform.h.in).

Regards,

[sanak]

TortoiseSVN diff file(Japanese)

[strk]

I've committed your patch and modified platform.h.in accordingly. Required also checking for finite() flavor in configure.in. Test from other unixers are very welcome.