Add reference commit for 2.6.0.

Rename GitHub organization.

Mark the commit for release 2.5.1.

Set branch and commit id for MetaR 2.5.0.

Remove local dependency on MPS extensions. Update languages and build…

… script.

Update build script.

Advance plugin to 2.4.4. Update build script.

New context menu to create groups/usages within the container.

Advance plugin to 2.4.2. Update build script.

Update build script.