created StreamID object

Intended as a more robust solution than mapping to the Stream* pointer, this
will map directly to the file and its index regardless of the Stream* pointer.

app/project/item/footage/stream.cpp

@@ -20,6 +20,7 @@
 
 #include "stream.h"
 
+#include "footage.h"
 #include "ui/icons/icons.h"
 
 Stream::Stream() :
@@ -114,3 +115,14 @@ QIcon Stream::IconFromType(const Stream::Type &type)
 
   return QIcon();
 }
+
+StreamID Stream::ToID() const
+{
+  return StreamID(footage_->filename(), index_);
+}
+
+StreamID::StreamID(const QString &filename, const int &stream_index) :
+  filename_(filename),
+  stream_index_(stream_index)
+{
+}

app/project/item/footage/stream.h

@@ -29,6 +29,17 @@
 
 class Footage;
 
+class StreamID {
+public:
+  StreamID(const QString& filename, const int& stream_index);
+
+private:
+  QString filename_;
+
+  int stream_index_;
+
+};
+
 /**
  * @brief A base class for keeping metadata about a media stream.
  *
@@ -84,6 +95,8 @@ public:
 
   static QIcon IconFromType(const Type& type);
 
+  StreamID ToID() const;
+
 private:
   Footage* footage_;