AMD compatibility + some build tweaks

That's what I had to do to have it working with StackEdit:

- Added the whole build folder in the repository. The reason is that I use bower to manage this dependency, and I only want to include `diagram-grammar.js` and `sequence-diagram.js` in my project.
- Fixed the AMD incompatibility issue. Raphael is not defined globally when AMD is enabled.
- Specified jison version in `readme.md`, as the latest version of jison is not compatible.