Proper comparison of floating point values in equals method

[karlnapf]

Shogun can compare any objects via CSGObject::equals. This goes through all the parameters and compares their content and is used for integration testing and other useful things.

We currently compare floating point numbers as
if (CMath::abs(a-b)<eps) ....

This is a very bad thing, as it does not handle NaN, inf, etc
See http://floating-point-gui.de/errors/comparison/

This task is to change the comparison to handle all cases of floating point numbers, for the types float32,float64,floatmax. It should be a very few lines only. You should add a correctly implemented (templated) comparison function for all sorts of floating point numbers in CMath and call this method from the TParameter::compare_ptype method.

This will also fix broken integration tests on OSX

[karlnapf]

fixed in #1939