Added IntelCompiler, IntelCCompiler and IntelCCompiler.
environments.py has been changed to detect icc and icpc.
ninjabackend changed for proper pch generation.
ICC 17.0.0 does not support C++13 (that's why default arguments tests fails).
Test 25 object extraction fails due to some unescaped whitespaces.
Some test with vala fail because of successful build, although they
should fail, as warning do not exit with failure.