Added MemcachedClientCache.ctor() that takes an IMemcachedClientConfiguration instance

Demis,

as mentioned on Google Groups here's the pull request for an added .ctor() that allows devs working with the MemcachedClientCache to provide a custom / predefined MemcachedClientConfiguration instance along with it.

I tried to adhere to the rest of the coding style inside the class & basically just did the following:

1. Added the new .ctor() (line #73)
2. Added a new private method that prepares the default configuration for the other two already existing ctor's (taking hostnames/ipEndPoints) (line #83)
3. ... and only perform the 'common' part (_client assignment & LogManager.AssignFactory() call) in LoadClient() (line #99)

Hope that's fine, if not, let me know what to change there.


Thanks!
-Jörg