Added the unsafe variable instructions.
Added test case for newly found bug, query arguments not unifying against structures correctly.
Fixed bug with constants in queries unifying too loosely. There was no default/fail case on the get_struc instruction.
Added failing test case for bug where variable in a functor binds to the functor top-level instead of its argument in a clause head.
Fixed bug where query variable in non-arg positions were being made void. All tests passing.