Infer which capabilities the tooling API provider supports based on inspecting which protocol types it implements rather than its version number.
Removed version from ModelIdentifier. It can be added later once we actually use it.
Javadoc updates.
Some polishing of tooling API model types:

- Added @since tags to a bunch of types and methods.
- Removed some redundant supertypes.
- Removed some inherited method declarations.
- Some javadoc edits.
Updated the 'standard plugins' chapter to add missing plugins, update the details of various plugins, and to shuffle some plugins around.
Use a consistent way of referring to incubating things.
Fixed default value for property of the JaCoCo extension.
Updated the template spec.
Add chapter about plugins in initscripts
Merge branch 'release'