Added a new optimized constructor to some readers (FFmpegReader, QtImageReader, ImageReader) to not Open() in the constructor, which dramatically speeds up creating hundreds of Readers (i.e. when opening a project). This is really only useful when inflating the reader with Json right after you instantiate it...

src/ImageReader.cpp

@@ -36,6 +36,15 @@ ImageReader::ImageReader(string path) throw(InvalidFile) : path(path), is_open(f
 	Close();
 }
 
+ImageReader::ImageReader(string path, bool inspect_reader) throw(InvalidFile) : path(path), is_open(false)
+{
+	// Open and Close the reader, to populate it's attributes (such as height, width, etc...)
+	if (inspect_reader) {
+		Open();
+		Close();
+	}
+}
+
 // Open image file
 void ImageReader::Open() throw(InvalidFile)
 {