Feature/jstl helpers

This set of changes adds a new JSTL tag library (a refactored one that was shown in AEMCAST #6) as well as a XSS filter to guard websites from nasties.

Other features include:
-Enhanced Include tag to let you specify XML of default settings for included component if it is blank/new
-Memory cache tag to cache things in memory for a limited duration of time, useful for speeding up slow parts of a page that do not change frequently.