Code drill feature parity, downloading snippets from github

Phase 1 and 2. Phase 3 will allow custom github repo input.

src/generator/mod.rs

@@ -3,7 +3,6 @@ pub mod capitalize;
 pub mod code_patterns;
 pub mod code_syntax;
 pub mod dictionary;
-pub mod github_code;
 pub mod numbers;
 pub mod passage;
 pub mod phonetic;