Blogging Roller

I made a couple of changes in the Roller 0.9.7-dev codebase to address memory usage:

1. There is now one and only one instance of the Roller business-tier implementation object RollerImpl instead of one per session.
2. Many calls to getSession(true) were removed and now the RssServlet no longer creates a session.
3. Velocity template caching has been turned back on, but I'm really not sure why leaving it off (apparently) ate so much memory.

#1 and #3 can be easily backported to Roller 0.9.6.X so FreeRoller can take advantage of them. My site now seems to be using memory at a much more reasonable pace now and I've survived 24 hours with max heap size set to -Xmx64m.