GSoC 2013: done with ImageIO - please test (update #5)

The imageIO section of the original project was much shorter than this. Originally it was limited to implement imformats, and then expand it to do the writing and reading of multipage images in a Matlab compatible way which is just implementing the options Index and Frames in imread, and WriteMode in imwrite. The date of that last commit was 16th of July. However, I didn't stop there and tried to fix other incompatibilities with Matlab and add new options.

Here's a list of the main changes:

In the end, I recognize that there's some incompatibilities left to fix but I don't know how anymore. As I mentioned on my previous post, GraphicsMagick is too smart for our use. I predict that we will eventually have to move to something different, if for nothing else, to read and write floating point images without trouble. I only had a quick glance on alternatives but FreeImage would seem like a good bet. Of course, there's also the possibility to write our library wrapper around the format specific libraries.

Would be nice if users could throw some images to imread and imwrite and report any bugs. I'm specially afraid of regressions since there was so much stuff changed and we don't really have tests for these functions yet.