I reorged labels on Cabal's GitHub

If you hate it I can change it back but give it a try for now. If the "component" prefix in "component: solver" is too long we could go for something like "C-solver" but I think that is less transparent. I also added some new labels, "paging: ezyang (...)". In the parenthetical should be a quick summary of the types of things you are interested in getting paged for. I tried to guess some but I am not perfect, please feel free to change your description / add a label for yourself (I didn't get everyone) / tell me how you want yours changed. Edward