add getters and setters for settings variables

[GoogleCodeExporter]

I am using JOpenSurf in an application and I want the user to change the 
parameters of the calculation at runtime. 

So it would be nice to have getters and setters for the settings variables like 
mNumOctaves, mThreshold or mBalanceValue in the Surf-class. Alternatively the 
access modifiers for those variables could be changed to protected, so that an 
inheriting class could access them and provide the getters and setters. 

Currently I have to copy the code in a new class and make the changes to the 
code myself, which is really bad programming style.

Also the final variable HESSIAN_INIT_SAMPLE, is not copied into a non-final 
variable before it is applied. In the current application it doesn't make a 
difference, but in order to change the value via a setters, it needs such a 
value just like the others.

Original issue reported on code.google.com by [email protected] on 15 Feb 2011 at 3:39