Documentation for FOG_CREDENTIAL usage

A customer asked how to use multiple sets of credentials with the cloud
provisioner. This technically has more to do with the fog gem than the
cloud provsioner itself - but is important for using the cloud
provisioner with multiple sets of infrastructure, regardless.
(releng) Move the location of the agent tarballs to a new dedicated download page
Add info on environments HTTP endpoint to the directory environments page
Edits to release notes (from eric0's suggestions)
Merge pull request #308 from shrug/master

(releng) Move the location of the agent tarballs to a new...
(DOC-639) changing pending to no-op in console screenshots
(DOC-639) changing pending to no-op in console screenshots
Facter 2.0.1 release notes
Mention interpolation of vardir and confdir in puppet.conf
Add sections on structured facts and aggregate resolutions to Facter 2 release notes
Add page on config file environments
Add more information to directory environments page

Stuff like accessing environment from manifests, info about the
HTTP api, and more.
Rearrange the 3.5 nav sidebar a bit

I was sleepwalking a bit when arranging these sections. Language should go
before a bunch of that other stuff, references should be higher and not have the
word "generated" in it (because who cares), the type reference may as well have
its own top-level item because it's just that important, and a few sections
should talk about what's included in them so readers know whether they want to
click.
Merge branch 'puppet35'
guts: Update canonical.rb to skip pages that already have a canonical link
Add canonical links to all new-for-3.5 pages
Soft-deprecate /guides/environment.html -- aim canonical link at reference page
Merge branch 'puppet35'
QSG edits
Merge branch 'master' of github.com:puppetlabs/puppet-docs