Revert 'presentation' dir to 0.81 code, add 'presentation2' for 0.9

This fixes an issue where recordings copied from a 0.81 server might not play back correctly on a 0.9 server.

This changes the 0.9 recording scripts to use playback support files from a different subdirectory, 'presentation2', while existing 0.81 recordings continue to use the 'presentation' directory.

If the raw files from an old recording are reprocessed, it will switch to using the newer playback support files.

**Note that this change will break all recordings made with previous 0.9 beta versions!**

Recordings made with previous 0.9 beta versions will have to either:
* Reprocess all recordings _or_
* Edit the metadata.xml in all recordings to change `presentation/playback.html` to `presentation2/playback.html`