README.md: add instructions on how to statically link
nbd: adding a lot of debug code
gammaray: embed linking libraries so static linking is easier
README.md: instructions for compiling with a custom library

+ Included toughest case of statically compiling
nbd: properly reconnect upon disconnect

+ uses "unused" hiredis struct element for this purpose
+ this is undocumented, but suggested by hiredis devs