bug system, "subscribe to a bug" added and other little things

Hi, As you may have noticed, I cleaned the pearweb bugs and added three little features: - logged pear developers do not need to enter their information anymore - A bug reporter can now give his name (use it in the changelogs) - You can subscribe to a bug without being the reporter or a maintainer it is activated only for pear members (logged) now, for test purposes. If everything is fine until friday, I will make it public. Please let me know if there is some errors or other required changes (especially the subscription). Thanks, --Pierre