added check to ProjectionAxes::createFBO() such that glDeleteFramebuffers and...

added check to ProjectionAxes::createFBO() such that glDeleteFramebuffers and glDeleteRenderbuffers are only called if the FBO and RBO have already been generated. OpenGL specs indicate it is fine to call these functions on non existant handles, like on the initial creation of the texture. This wasn't a problem on linux but it was for OSX. It was causing each projection plot to share a single texture and all spikes were going to a single plot. As when the 2nd projection plot called createFBO it deleted the FBO for projection plot 1 and 3 did it for 2, resulting in a single fbo for all plots.  This should resolve most of the projection plotting issues for mac