(PUP-2914) Add rgen 0.7.0 to vendored libraries

This commit adds the rgen 0.7.0 library by placing it in the vendor lib
that is needed for development on the new parser.
(PUP-2914) Remove rgen 0.7.0 dependency

The library rgen was an unnecessary dependency since it was
vendored. This commit removes unnecessary dependency.
(doc) Add Puppet Specific Documentation

Vendored libraries had no way for us to tell where they had come from or
what version the library was at.
This commit adds `PUPPET_README.md` files to each of our vendored
libraries to give us more information about where they came from.
(doc) Add documentation for environments api call

The environments resource was updated but documentation was not changed
to reflect the changes.

This commit adds the documentation to describe new functionality.
(PUP-2999) Use host.tmpdir for agent tmpdirs

PUP-2999 switched these two tests to use Beaker's new
create_tmpdir_for_user() helper, but this has a bug related to windows
acceptance (QENG-1108) in that it doesn't end up prepending a 'cmd.exe
/c' and we get pathing issues with our current acceptance setup on
windows.

Just switching back to using host.tmpdir calls for now; the original
changes were for jvm-puppet, but that is master only, and these are
agent calls.
Merge branch 'issue/master/pup-2999-agent-tmpdirs-on-windows'

* issue/master/pup-2999-agent-tmpdirs-on-windows:
  (PUP-2999) Use host.tmpdir for agent tmpdirs
Merge pull request #2994 from demophoon/maint/master/fix-http-environment-doc

(doc) Add documentation for environments api call
(PUP-1044) Ensure file bucket streams are closed at all times after use

This makes the stream() method on file bucket file take a block
to ensure that the processing of the stream always ends up closing it.
Merge pull request #2999 from hlindberg/PUP-1044_ensure-closed-filebucket-file

(PUP-1044) Ensure file bucket streams are closed at all times after use
(maint) Fix up regex in indirector rest spec 404 tests

Seeing sporadic failures on 1.8.7 with these two tests, probably related
to order of parameter keys not being guaranteed.  This patch loosens the
regex on these two tests slightly so that it the keys can be in any
order.

With Britt Gresham <britt@puppetlabs.com>
Merge remote-tracking branch 'upstream/pr/2995'

* upstream/pr/2995:
  (doc) Add Puppet Specific Documentation
  (PUP-2914) Remove rgen 0.7.0 dependency
  (PUP-2914) Add rgen 0.7.0 to vendored libraries