add top-level godoc: sample some parts of the README
add top-level godoc: sample some parts of the README

Signed-off-by: Erik Hollensbe <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@hollensbe.org>

gonkulator/libkv,KimTaehee/libkv,DIREKTSPEED-LTD/libkv,bsmr-docker/libkv,gonkulator/libkv,therealbill/libkv,zyclonite/libkv,therealbill/libkv,polyverse-security/libkv,sanimej/libkv,christophelec/libkv,chenchun/libkv,bsmr-docker/libkv,chenchun/libkv,moxiegirl/libkv,polyverse-security/libkv,zyclonite/libkv,KimTaehee/libkv,kasisnu/libkv,MHBauer/libkv,christophelec/libkv,bprashanth/libkv,moxiegirl/libkv,sanimej/libkv,DIREKTSPEED-LTD/libkv,bprashanth/libkv,MHBauer/libkv,kasisnu/libkv