looks good. though you may want to write something in there to keep people cross-platform and cross-compiler aware. Like "it is required to work in blah, blah blah" or "if it does not build in all three compilers/OSs, say so in the conflict area" or add two new catagories "Supported Compilers" and "Supported OS"
Good protocol, I like it. Could I suggest another type "bugfix", where you are fixing a bug in Irrlicht & not submitting new features?
Only thing that is a little lacking is a directory structure, for example (I don't know the layout of the Irrlicht code) what if I make changes to
irrlicht/source/util/someutil.cpp
irrlicht/source/core/list.cpp
Maybe the README file needs to list all changed files & their original location within the Irrlicht directory structure.