Scalarize comps

Reference issue

What does this implement/fix?

The world is not yet ready for typed comparisons. This reverts the default behavior for the comparison overloads to return an array of bool. However, an API for typed comparisons is added: a.cwiseTypedLesser(b). This returns a non-boolean array if a and b have the same type. In this way, expressions like e = a.cwiseTypedLesser(b).select(c,d) may be fully vectorized.

Additional information