add signatures

Data/Git/Config.hs

Data/Git/Delta.hs

Data/Git/OS.hs

Data/Git/Parser.hs

Data/Git/Path.hs

Data/Git/Ref.hs

Data/Git/Repository.hs

Data/Git/Revision.hs

Data/Git/Storage.hs

Data/Git/Storage/CacheFile.hs

Data/Git/Storage/FileReader.hs

Data/Git/Storage/FileWriter.hs

Data/Git/Storage/Loose.hs

Data/Git/Storage/Object.hs

Data/Git/Storage/Pack.hs

Data/Git/Storage/PackIndex.hs

git.cabal