holidays commit: having tested nlo exact virtual contributions and nlo exact real ones. Improved vegas integration for simple integrals, in vegas_adaptor.h. There is a way to avoid the external constant pointer, which we should definitely implement in the vegas adaptor class as well: this is done by passing the pointer to 'this' as a void* in vegas_callgit status and then cast it to the base integral class. The way forward should be the implementation of NLO exact, both inclusively and exclusively, after the holidays