It is very slow and unnecessary - the user can easily use operator[] or
getElement and setElement for any operation with a single element, not
just addition.

Distributed argMin and argMax are not implemented yet, all other
operations successfully pass all tests (which were unified with the
tests for Vector, VectorView and StaticVector).

Simplified expression templates: pow implemented as a binary expression rather than a special unary expression

getConstView should be always used for const operations, because
explicit is better than implicit. Overloading one method for cases which
have a completely different type (ConstViewType is *not* just a
const-qualified ViewType) can be very unclear (or even ambiguous) in
certain cases.

Also, templates were reordered so that related functions are next to
each other.

It is already defined in VectorViewExpressions.h

[ci skip]

Functors can also be better optimized by the host compiler, because nvcc sucks...

Fixed ambiguity between vector operations for StaticVector, DistributedVector and DistributedVectorView