Change instructions for non-root agents

Add non-root agents to the `no mcollective` group rather than disable MCollective
Correct formatting
Correct formatting
Add future parser Classes page

Now includes references to parameter types.
Moved future parser collectors page into 3.7 docs

I don't think this file has changed much yet, mostly because I don't
know what changes there are. I'm making a note to follow up on this ASAP.
Moved the future parser commments page

Comments are exactly the same AFAICT.
Moved future parser conditionals page

The original commit for these changes is here:
https://github.com/holguinj/puppet-docs/commit/96313ebe5983983238eb15fcd08ecefeeb7bdbaf
Moved future parser containment page

The only change I really made here was deleting the reference to [PUP-1597](https://tickets.puppetlabs.com/browse/PUP-1597).
move future parser datatypes page

A few important changes here: the empty string is now true, and looking
up a nonexistent key in a hash returns `undef`. I'm not sure whether
hash keys can be any scalar value now (I'm pretty sure they can), so I made a note of that.
move future parser resource defaults page

I don't think there are any real changes here.
move future parser defined types page

The main change here is adding parameter types.
move future parser exported resources page

I don't think there are any relevant changes here.
move future parser expressions page

This page has gotten a pretty substantial rewrite. The complete history
is at https://github.com/holguinj/puppet-docs/commits/3.6-future-lang/source/puppet/3.6/reference/future_lang_expressions.markdown
move future parser facts and builtin vars page

I don't think there are many changes here.
move future parser functions page

There aren't many changes to report, but this page doesn't address
lambdas yet, and it probably should.
move future parser namespaces page

I think the main change here was just removing the known issue.
move future parser node definitions page

The main issue here is that `import` no longer works in the future
parser, so that guts a pretty large section of this doc. What I don't
know is whether there's a replacement for that functionality.
move future parser relationships page

I know manifest ordering is going to be default in Puppet 4, but I'm
assuming that the future parser doesn't enable it.
move future parser reserved page

This page still claims that the set of characters allowed in node names
is undefined. Is it?
Removed note on function calls in string interpolation

Apparently this works now.