Qt Creator Plugin HOWTO documentation first and second cut

Signed-off-by: Abhishek Patil <abhishek.patil@vcreatelogic.com>

Merge-request: 145
Reviewed-by: con <qtc-committer@nokia.com>

doc/examples/preferencepane/modifiedfilelistwidget.cpp

@@ -0,0 +1,20 @@
+#include "modifiedfilelistwidget.h"
+
+#include <coreplugin/filemanager.h>
+#include <coreplugin/icore.h>
+#include <coreplugin/ifile.h>
+
+ModifiedFileListWidget::ModifiedFileListWidget(QWidget* parent):QListWidget(parent)
+{
+    // Show the list of modified pages
+    Core::FileManager* fm = Core::ICore::instance()->fileManager();
+    QList<Core::IFile*> files = fm->modifiedFiles();
+
+    for(int i=0; i<files.count();i++)
+        this->addItem(files.at(i)->fileName());
+}
+
+ModifiedFileListWidget::~ModifiedFileListWidget()
+{
+    //Do Nothing
+}