- Needs a new name :-)
- Closes #695

With this patch the Main group of the Pods project is also sorted.

Closes #647
Closes #588

This includes a fix for an issue which caused the use of the incorrect
specification for dependencies from external sources.

Closes #548.

- added support for manifest.lock.
- added support for checking specifications checksums.
- removed lazy repo update as the check for the specifications checksums
  requires an up to date repo.

Closes #604.

Closes #658.