Hack in upper bounds reflecting the fact that current Yoko and its deps ...

...builds with ghc-7.6.3 and semigroups < 0.13

Note -- this doesn't actually doing any of the work to bring things up to date for the latest versions of dependencies; this just codifies what the limitations are.  Alas "type-spine" seems broken in GHC 7.8, so fixing it a prereq to fixing Yoko.