implement entire project in nodes

Project items are now represented directly in nodes opening up more versatility and possibilities. This is the first iteration of this and will be buggy. Need to test thoroughly.

app/common/filefunctions.cpp

@@ -43,7 +43,7 @@ QString FileFunctions::GetUniqueFileIdentifier(const QString &filename)
 
   hash.addData(info.absoluteFilePath().toUtf8());
 
-  hash.addData(info.lastModified().toString().toUtf8());
+  hash.addData(QString::number(info.lastModified().toMSecsSinceEpoch()).toUtf8());
 
   QByteArray result = hash.result();
 

app/common/xmlutils.h

@@ -24,7 +24,6 @@
 #include <QXmlStreamReader>
 
 #include "node/param.h"
-#include "project/item/footage/stream.h"
 #include "undo/undocommand.h"
 
 namespace olive {
@@ -58,6 +57,15 @@ struct XMLNodeData {
 
 void XMLConnectNodes(const XMLNodeData& xml_node_data, MultiUndoCommand *command = nullptr);
 
+/**
+ * @brief Workaround for QXmlStreamReader::readNextStartElement not detecting the end of a document
+ *
+ * Since Qt's default function doesn't exit at the end of the document, it ends up consistently
+ * throwing a "premature end of document" error. We have our own function here that does essentially
+ * the same thing but fixes that issue.
+ *
+ * See also: https://stackoverflow.com/questions/46346450/qt-qxmlstreamreader-always-returns-premature-end-of-document-error
+ */
 bool XMLReadNextStartElement(QXmlStreamReader* reader);
 
 void XMLLinkBlocks(const XMLNodeData& xml_node_data);