Overhaul JspQueue, no functional change for Jasper.

Overhaul JspQueue, no functional change for Jasper.

- Rename class to FastRemovalDequeue, because
  it can be used gnerally. Nothing jsp related in it.

- Rename "head" to "first" as a better match for the
  existing "last"

- Switch previous and next: "previous" was
  pointing from first to last, "next" from
  last to first. Mind-bending.

- Add a bit to the description. Remove "ticket"
  language.

- Use more standard terminology "push" to
  insert in front and "pop" to remove from last

- Add methods shift and unshift for the operations
  at the other ends. Not used yet.

- Add remove() method (not used yet).

- Rename makeYoungest() to moveFirst() and add
  moveLast() (not used yet). This data structure
  doesn't actually know about young or old.

Add "Entry-" prefix to Entry.toString().

Rename makeFirst() in JspRuntimeContext to
makeYoungest(), because there we actually are using
timestamp information.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1028377 13f79535-47bb-0310-9956-ffa450edef68