Enable usage of gsl::narrow with exceptions disabled (#640)

Enable usage of gsl::narrow with exceptions disabled (#640)

* Enable usage of gsl::narrow with exceptions disabled

This solution uses the approach of boost::asio to enabling usage of the
library in environments where exception usage is either prohibited
or not feasible (due to code size constraints). A function template
gsl::throw_exception has been added, which in a normal environment just
throws the exception. However, when GSL_TERMINATE_ON_CONTRACT_VIOLATION
is defined the function is only declared by gsl and the definition of
this function template must be supplied by the library's user.

Closes: #468

Signed-off-by: Damian Jarek <damian.jarek93@gmail.com>
Addition:
- understand STL no exception macro
- use function static variable to set termination handler in kernel mode
- add compile-only tests for no-exception mode

* added termination tests and fixed bugs

* disabled warning C4577 for msvc 2015