The code wasn't compiling. Oops.

The actual release needs to happen in a lock step, as the new plugin
needs to require yet-to-be-released version of the core. So for the time
being it's a snapshot dependency, deployed in the snapshot repository.

Previously, the presence of the xpath parameter suppressed the tree
parameter processing. This change fixes that so that the tree parameter
can be used for building small DOM, then XPath to manipulate the data
further.

... so no need to complete it.

Added test whether the currently checked slave computer actually can take the buildable item before flagging it as needed (avoids powering up and connecting to slaves for jobs they can't build).

This is expected to improve the burst data transfer performance.

Narrowing it down to reduce the harm.

... so that we can expose them as an object that keeps track of
execution-scoped objects.

... not from user's point of view, but more from implementation point of
view (and this can be used to push SCM retry counts out of the core.)

To avoid cluttering the UI unnecessarily, adding isApplicable() to
SCMCheckoutStrategyDescriptor so that it can nominate itself only for
matrix projects.

For example, a common use cases are:

- skip the parent checkout and only do the checkout in MatrixRun
- check out only once in MatrixBuild and then let all MatrixRuns build from the same directory

Accoringly,

- renamed classes to drop 'Run' since now they cover 'Build' as well.
- instead of using the boolean return value to indicate the fallback to
  default, using some backdoor to have the default implementation do
  this. I think this keeps the abstraction cleaner for the implementor
  of the extension point.

Integrated a new version of Stapler that provides debug logging for the
problem. See the ticket for more details of how to enable this probe.

Update Spanish

Further reduce the scope of the lock to only cover jobNames access, which is mandatory. if ig.doCreateItem requires synchronization, that's a job of ig.doCreateItem implementation, not that of ListView.

It uses Diffie Hellman to come up with one-time session key, then have
the server sign this session key to allow the client to verify that
there's no man in the middle.