Add "browser" entry to package.json

Stupid Browserify needed this in order to *not* include some unnecessary shims and some "fs" and "path" module replacements when bundling the grammar.js file.
Change Cakefile to use sh to run commands
Add "Generated by" header to index.js bundle

Hopefully this makes GitHub recognise this file as generated.
Add lib/ to .gitignore
Add max reduction steps option