- Introduce separate Lock and LocalRepo transactions, one for changes
to the lock file, one for changes to locally installed packages based
on lock file
- Remove various hacks to keep dev dependencies updated and
incorporated the functionality into the transaction classes
- Remove installed repo, there are now local repo, locked repo and
platform repo
- Remove access to local repo from solver, only supply locked packages
- Update can now be run to modify the lock file but not install packages
to local repo
As it is faster to remove packages from the repos and keep them out of the
package pool to begin with, we don't need an installable() method on the
policy.