Chery pick merge of branch 'feature/is_callable'

Add implementation of std::is_callable

This is proposed for C++17 and helpful to checking correctness of predicates supplied to algorithms. This also commes with a test that checks is the behaviour is correct, especially with respect to various combinations of r-values, r-value references, and l-value-references.

See merge request !151 (merged)

Milestone changed to %DUNE 2.5.0

Added backport feature labels

Mentioned in commit 70ec21ea

Status changed to merged