[servletapi] javax.servlet.jsp.PageContext: help needed

I commit modifications to this class (javax.servlet.jsp.PageContext) but
I'm  not  sure it  will  work  properly.  The signatures  are  corrects,
compilation is good but I did not try the classe actually. 

Here is the changelog ONLY for this class ;)

* (include): IllegalArgumentException, SecurityException  do not need to
  be in the signature, only in the documentation

* (forward): IllegalArgumentException, IllegalStateException, 
  SecurityException do not need to be in the signature, only in the
  documentation

* (include): String path, boolean flush: new in JSP 2.0

* (handlePageException): Exception: [javadoc] throws 
  NullPointerException, SecurityException

* (handlePageException): Throwable: [javadoc] throws
  NullPointerException, SecurityException

* (popBody): new in JSP 2.0 but don't know if the implementation is
  good! Can someone check?

* (PageContext): removed a lot of methods that I did not see in the
  current specifications. 

* (PageContext): extends JspContext (JSP 2.0)

* (PAGE_SCOPE): 1 

* (REQUEST_SCOPE): 2

* (SESSION_SCOPE): 3

* (APPLICATION_SCOPE): 4

NOTE: I don't know  if we must keep the same values  as the original jsp
      api. If  we do, we  have to replace  the values in the  sources by
      these ones. BUT: these values  are defined in the parent class, so
      we can also just erase the four properties in this class.

* (getSession): is an abstract method!

* (getPage): new abstract method

* (getRequest): new abstract method

* (getResponse): new abstract method

* (getException): is an abstract method!

* (getServletConfig): is an abstract method!

-- Arnaud Vandyck, STE fi, ULg
   Formateur Cellule Programmation.