no Travis for now, I'm aware stuff is borked
wip: mirror prims in core.prim
delay _const differentiation until middle end

this keeps the front end simpler and will help solve an impending
dependency problem where we don't want the prim syntax defs in the
core package to depend on api classes like Nobody and LogoList,
which are engine details
wip first stab with many FrontEndTests now passing

but many failing too
wip more progress, tc Passed 476
wip more progress, tc 506 passing
wip minor cleanup
wip more progress, tc Passed 567