feat(docs): added support for the doc app to show its associated Git SHA id/link

Gulp mods still needed to to inject the SHA value into the JSON file.
docs(demos): source view components not set `display:none` when source is **not** shown.

Closes #234
Closes #240
fix(tabs) - resolved TypeError in autoFocus()
feat:(docs) add version.json generation to build process

closes #235

fixes for wip-sha docs
fix(material-list): Add semantics
fix(material-dialog): Focus mgmt, ARIA attributes
test(dialog): Adding test coverage for ARIA