Added LICENSE file.
Added LICENSE file.

Stefan Groschupf as copyright holder.

Signed-off-by: Peter Voss <59bd0a3ff43b32849b319e645d4798d8a5d1e889@petervoss.org>
sgroschupf/zkclient,livvyguo/zkclient,fpj/zkclient,NBSW/zkclient,gityf/zkclient,erikdw/zkclient,wgpshashank/zkclient,ijuma/zkclient,Parth-Brahmbhatt/zkclient,fengbaicanhe/zkclient,patilavinash/zkclient