Use anotations instead of @UML tags

Current source code maps Java interfaces/methods to UML identifiers through javadoc @UML tag (a custom tag added especially for this project). The anotation mechanism provided in J2SE 1.5 would offer a better mechanism. We are not allowed to release 1.5 dependent code, but we can use it as a temporary step for javadoc building (we already use generic type for that). Anotation would also help to check Java interface compliance regarding OGC's UML through an automatic script (since anotations can be checked at runtime).