Add an option for caching the results of Class.forName in DefaultCreator

[rlodge]

During performance testing we discovered that calls to Class.forName were taking a large amount of time relative to our expectations. We'd like to have an option for caching the results of the class name lookup so that the forName method is only called on new classes.

[evanchooly]

That happens in a number of places in Morphia. Any particular hotspot giving you problems?

[rlodge]

DefaultCreator. We've made a change and seen a 10-12% performance improvement, at least in our case. I'm preparing a pull request.

[evanchooly]

excellent. I look forward to seeing it. it won't make the 1.0 cut but we can do a 1.0.1 release soon enough.

[rlodge]

Works for me, as long as it's on the roadmap.