Merge pull request #268 from zacharyalexstern/master

Added free space psql vaccuum note.
Parenthesis are mandatory with rvalue-functions

This fixes a problem with the reference documentation where it was not
explained that parenthesis are only optional for statement-level
functions.

Here is an example :

    $a = function "argument" $b = literal

With the "old" parser, this will result in a parse error. With the new
parser, it seems that it is interpreted like this :

    $a = 'function';
    'argument';
    $b = 'literal';

Which might cause puzzling bugs.
Merge pull request #269 from bartavelle/master

Parenthesis are mandatory with rvalue-functions
Small wording change in function reference
Update install_options per DOC-228
Add 2.7.24 and 2.7.25 release notes
Merge pull request #270 from skottler/2.7.x_updates

Add 2.7.24 and 2.7.25 release notes
Update to RHEL6 instructions, requires additional channel

To install puppet on RHEL6, an additional channel (repo) is required,
the RHEL6 Optional Channel. Rather than provide explicit directions, as
they have changed a few times over the life of RHEL6, a link is provide
to redhat.com for the viewer to follow.
Merge pull request #271 from rnelson0/rhel-optional-url

Update to RHEL6 instructions, requires additional channel
Minor change to external fact guide

clarified location of external facts directory for OS X and included
information about the `—external-dir` option (FACT-16).
Update "Bug Tracker" link

Now points to https://tickets.puppetlabs.com. Also deleted links to the
old wiki. (DOCUMENT-17)
Added documentation for UUID fact

Addresses DOC-241
Slight cleanup of core facts documentation

Mosty just for consistency and punctuation.
Fixed incorrect certnames on install_what_where. See DOC-463.
Fixing cert name mistake in older versions. See DOC-463
Catch a dead link in Learning Puppet
Added documentation operatingsystemmajrelease fact

Addresses DOC-319
changing 'noop' to 'no-op' except for code examples
Added information about MOAR to Learning Puppet

Somewhat related to DOC-430.
Added known issue for DOC-449 on 3.1.