Reorganize into flat structure, lock deps

* Rename app from bookshelf_wi to bookshelf
* Switch all config to use bookshelf app key
* Move src to top-level and adjust rel building accordingly
* Update Makefile for common template targets and dep locking
  goodness.
* Add rebar.config.lock
* Reformat reltool.config for automatic version bumping
* Add required ascii art for release generation