Clean: Update glossiness API, to be able to have a default specular color if none provided

[FarhadG]

A more intuitive glossiness API, along with a default specular color if none was provided (based off the light color).

[FarhadG]

Just FYI, this will break the old API, as the previous one required that you pass in a Color as the first argument (if not a material express) with a strength. Now, on the other hand, you pass in strength as the first argument and an optional Color for the second argument.

I will push up a demo for this, very soon.

[FarhadG]

All updates have been made and here's a DEMO showcasing the updates.

@michaelobriena

[michaelobriena]

@FarhadG Can you update the commits so that the second commit is marked as a breaking change?

Thanks.

[FarhadG]

Updated to breaking commit.

@michaelobriena