Remove explicit import of NotStrict - fixes #492 (#494)

* Remove explicit import of NotStrict - fixes #492

* Provide macro for MemBase.apply().

* Provide macro for MemBase.apply().
Since a macro cannot override an abstract method, provide a concrete
apply method n VecLike() that we can override with a macro.

* Remove concrete apply() in VecLike.
Since MemBase no longer extends the trait VecLike, we do not require a concrete method to which we can apply a macro to extract the appropriate CompileOptions.