Vcs: Add Fossil SCM integration plugin

* Qt Creator base-commit: f77af5e336
* Stand-alone plugin source tree for integration into qtc super-project
* Original release: https://github.com/nomadbyte/qtcreator-plugin-fossil
* Adapted from Bazaar plugin implementation

Configuring Fossil
------------------

1. Download the [Fossil SCM client](http://fossil-scm.org) and install `fossil`
   executable file in your `PATH`.

2. Create or designate a directory to store local Fossil repositories and
   remote clones. For example: `~/fossils/qt`.

3. Configure Version Control Options for the Fossil plugin to use
   the designated directory as `Local Repositories Default path`.

Now Fossil should become available as a VCS choice to create new local
repositories, as well as a choice in `New File or Project` to clone a
remote Fossil repository.

Change-Id: I630184c1b344184d9e08ae2fc24a5e4766f834b9
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

plugins/fossil/annotationhighlighter.cpp

@@ -0,0 +1,51 @@
+/****************************************************************************
+**
+** Copyright (c) 2016 Artur Shepilko
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include "annotationhighlighter.h"
+#include "constants.h"
+
+#include <utils/qtcassert.h>
+
+namespace Fossil {
+namespace Internal {
+
+FossilAnnotationHighlighter::FossilAnnotationHighlighter(const ChangeNumbers &changeNumbers,
+                                                         QTextDocument *document) :
+    VcsBase::BaseAnnotationHighlighter(changeNumbers, document),
+    m_changesetIdPattern(Constants::CHANGESET_ID)
+{
+    QTC_CHECK(m_changesetIdPattern.isValid());
+}
+
+QString FossilAnnotationHighlighter::changeNumber(const QString &block) const
+{
+    QRegularExpressionMatch changesetIdMatch = m_changesetIdPattern.match(block);
+    if (changesetIdMatch.hasMatch())
+        return changesetIdMatch.captured(1);
+    return QString();
+}
+
+} // namespace Internal
+} // namespace Fossil