Adding public "is_renderable" function to text module

[QuantumFractal]

Why? Fixes #67 I wrote a hack, now I'm cleaning it up 😛

What's changed?

• Refactored font_array to be module level variable.
• Pulled score_font out of AnimText class.
• Added is_renderable from the aforementioned hack.

Testing Pulled my fork as a dependency in the ace bot. Testing thread Rendered Video

[LuisMayo]

Perfect contribution. Thanks!