Start a TODO

Signed-off-by: Michael Livshin <dev@cmm.kakpryg.net>
Clean up jet definition mechanism a little

Signed-off-by: Michael Livshin <dev@cmm.kakpryg.net>
Jet macros can now take an environment

Not sure what for, but omitting the ability seemed sloppy.

Signed-off-by: Michael Livshin <dev@cmm.kakpryg.net>