Round Flag Icons + Helper Utils

[xsorifc28]

Previously I had PR'ed a version with round flags, but these were resource files which made the library size bigger.

This PR removes those files and adds a programmatic way to generate round icons (via bitmap or resource id).

Also added are some methods to get the country code via name and vice versa.

I found these helpful. If you have any questions, or there are any incompatibilities, I'm happy to resolve.

Let me know your thoughts.