[Core] Cleaned up all HTML tags
[Core] Improved generator-related API
And added unit tests
[Core] Improved the bundle declaration mechanism
Both asset type and name are now optional. They are deducted from the first location found.
Added lots of new checks for consistency of bundles.
Added a new "bundle.location" config property, only used for testing purpose, allowing to tell bundle loaders to load JSON files in a specific folder.
Generally speaking, formatting and consistency errors are now buffered before being flushed in a DandelionException.

Closed #11
Closed #37
Closed #38