The "tf" command that ships with Team Explorer Everywhere is pretty good, but

it is missing some functionality that we'd like. Most notably, there's no way

to get the content of files within a shelveset without unshelving it. That

means that in order to be able to post shelvesets, we need our own adapter.

This change is the beginnings of such an adapter, using the TFS SDK for Java.
Because we have such an adapter now, we can make it do exactly what we need for

interacting with TFS, which dramatically reduces the number of times it needs

to be called. This is good because each time it is called, we have to spin up

the whole JRE.
I've written this using a modular command format with individual commands for

each of the steps we have. These steps are:

Verify the workspace and get the URL of the collection.
Parse a given revision spec (with zero, one, or two "revisions" specified).

  This converts those revisions into either numeric changesets or special

  internal keys representing either the working copy or a shelveset.
Do a diff based on the parsed revisions. Diffs are currently implemented for

  the working directory and shelvesets. I haven't yet implemented diffs for

  committed revisions, because that's somewhat more complex, but the existing

  tf.cmd-based implementation doesn't do it either.

This does not yet handle rbtools' -I and -X flags.

Used this to post pending and shelved changes.