unit-threaded v0.8.0

[Atila Neves]

New release of unit-threaded, the advanced test framework for D:

https://code.dlang.org/packages/unit-threaded

Besides bug fixes, the main difference is now cartesian product 
of types works as it did for values when it comes to 
parameterized tests:

------------------
@Types!(ubyte, byte)
@Types!(int, uint, float)
@UnitTest
void fun(T0, T1)() {
     static assert(T0.sizeof == 1);
     static assert(T1.sizeof == 4);
}
------------------

This now generates 6 tests, one for each combination of types, 
similarly to what already worked with the @Values UDA.