Added the ability to specify a custom encoder instead of the default marshal encoder.
Removed private key file.
Updated encoding to support flags.
Updated to allow the memcached encoder to update the flags.
Updated memcache multi-get to preserve flags for each key, to pass to decode.
Updated memcache to avoid an extra array create when not necessary.
Updated memcached to pass in keys and flags to the encoder.
Merge remote-tracking branch 'evan/master' into encoders

Conflicts:
	memcached.gemspec
Merge pull request #118 from expectedbehavior/encoders

Allow custom encoders