Cache PropertyInfos in AutomaticMapper

[joeyb]

The AutomaticMapper<TSrc, TDest> class currently does no caching and re-grabs the PropertyInfos for the src and dest each time the mapping is run. This can be sped up by caching those during the first mapping so that subsequent runs don't need to do it.

I'm still trying to decide whether the PropertyInfos should be cached per instance or statically. I'm leaning towards doing it per instance because I think that fits the philosophy of the project better by leaving that cache lifespan decision up to the IoC container. That would allow the cache to actually be garbage collected if needed.

[joeyb]

This was fixed in 81b2833. The cache is done per instance so that its lifetime is up to the IoC container.