Added a list for containing all the not includable headers

Added a text file containing the list of all the currently non-includable (out of the box) header files distributed with the dev package. I'm not sure where this should go and this seemed like a reasonable place. Perhaps it would be better placed in the wiki but I don't know if anyone looks there. Also, I made the hphpize script executable out of the box (maybe this should be in its own PR but it is a very small change).