Version 2.6.3 released.

This version has a few minor changes and lots of additional tests. It should now be possible to use all of gsl 2.6 except some functions like sorting built into the C++ standard template library through ccgsl. Nearly everything that used pointers to arrays can now use std::vector<t> or gsl_vector instead. Nearly all gsl functions that take function pointer and void* param arguments can use C++ functions or function objects instead.</t>

There are a very small number of funtions where a pointer parameter has been replaced with a reference parameter to make it clear that an array was not expected. These could produce compile-time errors that are easily fixed.