JSTL 1.2 patch applied

I finished my first pass through the patch and applied it. I put a
fair amount of info into the commit message - I think it's worth
reading for the link to the spec update page and then the breakdown of
which files relate to which change.

    http://svn.apache.org/viewvc?view=rev&revision=728565

I've some open items for discussion:

* Look at the question in SetSupport.java and resolve.
* Look at questions in the length method in ForEachSupport.java
* Look at commented out code in prepre in ForEachSupport.java
* javadoc for new Expression classes
* Ensure equals()/hashCode() is fine in new Expression classes

# Not covered and suggest cactus tests are implemented for each if possible:

    *  Example involving <fmt:parseDate> in section 9.9 was incorrect.
A pattern has been added so the date can be parsed properly.
    * Clarified the fact that the output of <c:url> wont work for the
url attribute value of <c:import> for context relative URLs (URLs that
start with a '/'). (section 7.4)

# Create cactus tests for JSTL change #1
# Create cactus tests for JSTL change #2