Remove special casing on primitive types by casting 0 to type.

[airblast-dev]

This change will allow using more primitive types with the macro by casting 0 to the provided type.

Types that can be casted from a zero include but are not limited to; All numeric types, char, *const T (raw pointer).
Meaning special casing for f32, f64 and char can be removed. Which were added after issue #2.

I have tested compile times in a small application, but noticed very little, to no difference.

One more very small thing this helps in is syntax highlighting in editors, since the macro takes a type rather than a literal type name it displays the correct color for it. See screenshots from the testing file below.

OLD:

NEW:

[airblast-dev]

If using a null pointer (since 0 cast to a raw pointer, points to null) when storing raw pointers seems too dangerous even though it is just a placeholder, another branch could be added to the macro to explicitly disallow that type (by literal input matching), and then by using compile_error! We could give nice and helpful compile error. I don't think this is needed, since it should be impossible to happen, but I think it is worth mentioning.

[rossmacarthur]

Thanks for the contribution :)