Firm up the new rendering module implementation

Continue where the work was stopped for the 1.5M2 release. There are still lots of things to implement:

• Link parsers + link rendering (WikiSyntaxRenderer)
• Caches
• More syntax support
• Finish implementing the xhtml, velocity macros (parameters support)
• Implement all missing macros (all the radeox macros we had)
• Modify document link saving (no need for rendering, just parsing)
• Make preview work
• Find a way to move all old rendering code to a separate package so that it can be easily removed later and so that we have some clean code left (if possible)
  ... and a lot more I'm sure (this list should be edited as we progress)