Re-enable metadata

This is a simplistic Hash parser, but it works for basic metadata
purposes which seems better than having no metadata support at all.  The
following examples show how to set a page title using metadata.

All on one line:

<!-- --- title: My Fantastic Page -->

Or split across multiple lines:

<!-- ---
title: My Fantastic Page
-->

Notes:

1. Only one key/value pair per line. Multiple lines must be used for
multiple key/value pairs (though I'm not aware of support for any keys
other than "title").

2. Keys and values cannot contain embedded newlines.

3. The patch does *not* HTML-sanitize the key or value portion of the
metadata.  Presumably metadata is not solely for inclusion in HTML, so
only the user of the metadata will know whether it needs to be sanitized
in any way.
Add support for on-disk file references.
Add symlink support to on_disk files.
Fix realpath() on Ruby 1.8.
Merge pull request #27 from cpence/master

Add support for references to files on disk
Release 1.0.3
Require pathname when needed, should fix gollum/gollum#728.
Drop 1.8.7 support on Travis (It's broken)
Drop 1.8 support
Merge pull request #29 from cpence/master

Require pathname when needed, should fix gollum/gollum#728.
Strip text resembling HTML tags from metadata

Each line of a metadata block has all HTML-like tags removed before
parsing.  Basically this removes all text contained between and
including '<' and '>', but it is not "greedy".  For example, the
metadata:

title : The <, ==, >, and <=> Operators

would be stripped to:

title : The , and  Operators

It would NOT be stripped to:

title : The  Operators

The metadata test have also been re-enabled.
Merge upstream changes
Fix wording of metadata stripping test caption
Merge pull request #30 from david-macmahon/master

Re-enable metadata (try 2)
Updating a page in a wiki with the page_file_dir configured will always leave a staged commit after the save.

A wiki with a page file directory configured will not do a proper checkout during the update working directory process, leaving a staged commit, due to a duplicate page file directory prepended to the path. An existing page retrieved during the update process will already include it's full path, including the page file directory, in the page path so it doesn't need to be added to the dir during the update.
Merge pull request #31 from ddeyoung/update_page_with_pagefile_dir

Updating page with the page_file_dir configured will leave a staged commit
No need to use old versions of sanitize/nokogiri now that we require 1.9
Add an :allow_uploads wiki option

This is needed for PR #725 against Gollum to add file upload
functionality.
Merge pull request #33 from amenonsen/allow-uploads

Add an :allow_uploads wiki option
Merge pull request #32 from amenonsen/dependencies

No need to use old versions of sanitize/nokogiri now that we require 1.9