Use browserify to modularize the project.

This commit sets up the browserify infrastructure without pulling the
source into separate modules. Source is now in src/opentype.js.
Generated files are opentype.js and opentype.min.js, and are always
included.
Update the `ot` command to use new module system.
Var statement at top of file is silly.
Add the CONTRIBUTING file.

This file is based on D3's CONTRIBUTING file.
Forgot to include generated files in prev commit.
Automatically generate bower.json.

This picks up the version information from package.json.
Extract Path, line and parsing functions into modules.
Integrate development server in Node.

This server serves the static files and watches the `src` directory for
changes and compiles them (using watchify).
Extract all tables and objects into modules.