Update StableStore documentation based on #29

stable.go

@@ -4,8 +4,12 @@ package raft
 // of key configurations to ensure safety.
 type StableStore interface {
 	Set(key []byte, val []byte) error
+
+	// Get returns the value for key, or an empty byte slice if key was not found.
 	Get(key []byte) ([]byte, error)
 
 	SetUint64(key []byte, val uint64) error
+
+	// GetUint64 returns the uint64 value for key, or 0 if key was not found.
 	GetUint64(key []byte) (uint64, error)
 }