switching everything over to []byte, abandoning merkletree for now

common/engine/filehashing.go

@@ -1,14 +1,18 @@
 package engine
 
 import (
-	"github.com/kalafut/imohash"
+	"crypto/sha256"
+	"io/ioutil"
 )
 
-// UniqueFileHash creats a fast hash of a file. It's not bullet proof (could cause a collision, but in practice unlikely) but its fast
-func UniqueFileHash(src string) ([16]byte, error) {
-	hash, err := imohash.SumFile(src)
+// UniqueFileHash uses SHA256 to create a hash of the file
+func UniqueFileHash(src string) ([]byte, error) {
+	file, err := ioutil.ReadFile(src)
 	if err != nil {
-		return [16]byte{}, err
+		return []byte{}, err
 	}
+	hasher := sha256.New()
+	hasher.Write(file)
+	hash := hasher.Sum(nil)
 	return hash, nil
 }