- Implement 107 wrapper (issue #70)

Okay let's start this review, see how far we get. Will be very surprised if there are *not* iterations on this.
Once we start picking apart pieces of it as well I can make some smaller commits that isolate the changes

Notes:
- Implements the 107 API
- includes Louis' changes for issue #21
- Passes the TCK but there are many other tests needed:
  - unit tests of a good deal of the 107 module code and things the TCK doesn't cover
  - tests for changes made in ehcache proper
- `Store` has new variants of computeXXX() methods that control what happens when the compute function returns the same thing as the existing value in the store
- Ehcache `Expiry` now has a method for update vs. create. 
- There's a relatively hacky class `Jsr107Cache` that exposes cache operations unique or with different semantics that ehcache
- There is no integration with `ResilienceStrategy` for the cache ops that are unique to 107
- Some stats changes:
  - cache "hits" registered for conditional ops that fail, but for which the key was present
  - same thing for "misses" when conditional ops fail b/c the key doesn't exist
- removed the clear() methods from our statistics classes. That is a 107 only thing now



We started out with the `ehcache://default` being "static" actually... but looking into what other providers do, we thought it'd be nice to keep to bar to trying ehcache as an alternate provider as low as possible. So the idea is to let someone migrating from some other provider, overwrite that default behavior to use the `default CacheManager` with pre configured Caches if he _needs_ to...