Correct license to 3-clause BSD in poms.
Clarify comment.
Remove dead target: locker.actors
Untangle classpaths related to doc targets.
Generate scaladoc for each subproject.
Continuations plugin gets its own osgi source bundle.
Inline src/build/pack.xml into build.xml.

It tended too easily to get out of synch with build.xml.
Simplify packing, align maven-deploy and pack-maven.
Support publishing to maven from main build

Publish to maven with `ant publish.local`,
`ant publish`, or `ant publish.signed`.

For now, we must keep copying `src/build/maven/maven-deploy.xml`
to `dists/maven/latest.build.xml`, along with its dependencies,
as it's used by jenkins jobs and PR validation.

TODO: `inline src/build/maven/maven-deploy.xml` into `build.xml`.
Towards minimal build for publishing core to maven.

Use `unless` attribute in targets so that `docs.skip` influences dependency graph.

Create `scaladoc` task in `pack.core` so that we don't need `pack.done`
for publishing the core.

Move source bundle creation from `dist.src` to `osgi.core`/`osgi.done`.

Split dependencies of maven publishing into core/all variants:
`osgi.core` creates osgi bundles for just lib/reflect/comp.
Targets for publishing core to maven.

`ant publish-core-signed-opt-nodocs` creates and publishes the smallest
possible set of jars (library/reflect/compiler) we can send to maven.
It uploads jars with class files and sources, but no docs
(so that we don't need to build scaladoc or any other modules).

`ant publish-core-signed-opt` is similar, but also publishes docs.

For local experimentation: `ant publish-core-local-nodocs`.
With a little bit more work, this can be used instead of `replacestarr`.
Build cleanup. Prepare for scaladoc module build.
Fail build on error in signed maven publish.
Tidy pom xml files.
Bundle source and class file bundling in osgi bundling.

Fix oversight in not skipping scalap's ad-hoc published docs on docs.skip.
Merge pull request #3069 from adriaanm/build-maven-publish

Rework build to allow publishing core to maven