ImageData: limited support for integer pixel formats.

For now this doesn't support conversions (get/set/mapPixel, etc). Just the ability for ImageData to contain integer pixel contents, for example via Canvas:newImageData.

src/common/pixelformat.h

@@ -157,11 +157,21 @@ bool getConstant(const char *in, PixelFormat &out);
 
 const PixelFormatInfo &getPixelFormatInfo(PixelFormat format);
 
+/**
+ * Gets the name of the specified pixel format.
+ **/
+const char *getPixelFormatName(PixelFormat format);
+
 /**
  * Gets whether the specified pixel format is a compressed type.
  **/
 bool isPixelFormatCompressed(PixelFormat format);
 
+/**
+ * Gets whether the specified pixel format is a color type.
+ **/
+bool isPixelFormatColor(PixelFormat format);
+
 /**
  * Gets whether the specified pixel format is a depth or stencil type.
  **/