Add dynamic dialog button text
Update generator
Add dynamic name/author
Implement grammar variables and fix and improve designer

Variables can now be added to a grammar, and they're available with
Baba.variable.set() or through command-line arguments for exported node
executables.

The designer has been renamed and some text has been rewritten, god
knows what would be a good, descriptive title/subtitle for this
project. It's not really just a grammar designer anymore as it exports a
full generator with both a grammar and transforms, but it could be
renamed later if necessary.
Add probability of appearing for grammar nodes
Update site text generator
Implement confirm/prompt dialogs
Update site text generator
Fix Vue error on empty grammars
Use browserify/CommonJS and browserify transforms
Fix magnific popup dependency on window object
Ditch browserify in favor of webpack

The site has been updated to take advantage of several features of
webpack, e.g. lazy loading of uglifyjs and incremental packaging. Some
code has been refactored to use features like raw code insertion from
webpack, and a separate production task has been added to gulp.

TODO: handle live reloading of JS files
Trigger livereload in webpack task

TODO: proprely utilize webpack hot module reloading, asset hashing, etc.
Disable livereload on production build
Enable webpack caching and source maps
Fix string.js function call