seperate empv-hydra or wrap it with with-eval-after-load

[Vonfry]

Because hydra is an optional dependency in empv which isn't listed in melpa recipe, bytecomp canot work on empv-hydra by default. If a user bytecompiles everything downloaded, it will be failed on empv-hydra, due to packaging with empv togather. This situation is common in a distribution like nixos/nixpkgs which prebuild (bytecoomp) every files in package with no matter users use it or not, where hydra isn't in dependencies and empv-hydra is here.

Suggestion:

1. seperate empv-hydra to anther package
2. add with-eval-after-load in empv-hydra

[isamert]

Thanks for the heads up! I sent a PR to MELPA. Two different packages makes sense. with-eval-after-load still introduces byte-compile warnings.