Javadoc simplification: replace some custom {@note} tags by CSS. Advantages:
* Easier to maintain since editing the CSS produces immediate result (no need to recompile plugin and javadoc).
* More control on the title ("Note", "API note", "Implementation note", "Note for implementors", "Compatibility note", etc).
* Allows to use {@link}, {@code} and other usual javadoc tags.
* Better rendering in IDE help window.

Inconvenient:
* Slightly more verbose (but not that much).


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK7@1572252 13f79535-47bb-0310-9956-ffa450edef68