Rust bindings to taglib

NOTE: This repository is currently designed to circumvent some limitations with the default taglib behaviour/interface. To this end, it includes a fork of taglib as a submodule, and so must either be cloned with the --recursive argument (i.e. git clone --recursive <repo>), or the submodule must be initialised after this repo is cloned using git submodule update --init --recursive. Adding the ability for end users to actively configure this is a feature that is planned for the future. At present, however, using any other version of taglib will result in compile errors at the tag_c interface.