views should not do elementwise comparisons for equality operators.
they are pairs of iterators and are only equal if their iterators are
equal.
instead, use `equal` for elementwise equality. we update the name of
exactly_equal to perform this operation too.
GCC produces ODR error when including paths of the form './foo' and
'foo' in the same binary. Rather than managing duplication we just
universally pick the absolute form over the relative form.
