[boost] [egg] some comments

I'm attaching some comments after a not-so-brief reading of the egg documentations. I've started the review a while ago, so some of the comments (especially those about static initialization) might be obsolete after the long discussion I had with the author in another thread, but Shunsuke Sogame might want to respond again for those that missed that thread. This is not yet a complete review, I want to spur further discussion on this library (especially on the documentation) before providing a final review. Finally I would like to encourage others to review this library (no reviews yet and we are in the second week!) because it provides some extremely needed functionalities. -- gpd