Multiverse 0.7 almost complete

[peter veentjer]

he Guys,

I hope to complete Multiverse 0.7 this month.

Most important additions:
- support for isolation levels (read committed, repeatable read,
snapshot (default) and serialized)
- support for propagation levels
- support for trace levels (for debugging)
- support for pessimistic lock levels (so locks all reads/writes)
- commute
- alter
- pessimistic locking
- ensure (like the select for update in oracle)
- privatize (allows you the prevent any reads/writes to a
reference).

And the central clock is removed, so it scale considerably better. And
the performance also is improved (a lot). A generate a lot of java
code e.g. for the primitive types and I also generate different
transactions based on certain options.

The new engine was almost a complete rewrite.