Fixes list referencing issues

* Any iterable returned by find all was plainly backed by the
  values in the hash map. During delete action there was a
  concurrent modification exception. Solved here by ensuring
  that we crate a new `detached' list as a result of find all.
Updates servlet example

* Trying out how the JSP code, and the more pure server-side
  aspect, will blend with each other. This adds an implementation
  that's just crazy pragmatic, string-parsing, if-blocks for
  each `action' and so on. But for an end user, you can add,
  check, uncheck, delete and clear completed tasks.