Added pan + zoom to diagram viewer; show_diagram() didn't return; added PyQt, PyOpenGL, NumPy as dependencies in the docs
#include <utilities/log.h>
#ifdef LOGGING
static rlog::RLogChannel* rlFiltration = DEF_CHANNEL("topology/filtration/info", rlog::Log_Debug);
static rlog::RLogChannel* rlFiltrationDebug = DEF_CHANNEL("topology/filtration/debug", rlog::Log_Debug);
#endif // LOGGING