Algorithm for extracting information and generating dependency info

[bvssvni]

See #1

fn extract_dependency_info_from(extract_info: &str) -> Result<String, String>;

[bvssvni]

Maybe use hyper to get the Cargo.toml from Github. There is some example code here https://github.com/PistonDevelopers/asset_store/blob/master/src/iostore.rs#L180-L192

[bvssvni]

• Add a function for loading a text document from url into a String
• Add meta syntax for extracting dependencies from Cargo.toml
• Add struct Extract for extract information
• Add struct Dependency for storing dependency name and version
• Print out data in the custom format for dependencies and versions