Work in progress- relative URIs

Making template and CSS URIs relative to the library in which the type which is annotated resides.

Also making all URIs within the template and CSS files be relative to those files.
Code cleanup based on feedback:

- Changed AbsoluteUris to be top-level methods rather than all statics.
- Clarified unittest for Image by setting attributes rather than src directly.
- Changed multi-line comments format from /// to /** syntax
Additional cleanup items

 - package-relative URIs are now 'packages/' rather than '/packages/'.
 - Support for mirrorless mode with a transformer. This transformer generates
   one large table for type->URI lookups.
 - Integrated with tip-of-tree Angular

This generates a global table of type to URI lookups