## 2016-11-08 Diff-Match-Patch again, #Jens

When implementing not-git-only conflict resolution when saving over an already edited file, we 
have to perform a three-way-merge. And here we can fall back on Google's excelent diff-match-patch lib. 

```JS
import diff from 'src/external/diff-match-patch.js';

var a = "abc"  // Source
var b = "abc2" // Edit 1
var c = "a3bc" // Edit 2

var dmp = new diff.diff_match_patch()

var diff1 = dmp.diff_main(a, b);  // 0,abc,1,2
var diff2 = dmp.diff_main(a, c);  // 0,a,1,3,0,bc
// dmp.diff_cleanupSemantic(diff1);

var patch1 = dmp.patch_make(diff1)
// @@ -1,3 +1,4 @@
//  abc
// +2

var patch2 = dmp.patch_make(diff2)
// @@ -1,3 +1,4 @@
//  a
// +3
//  bc


var merge = dmp.patch_apply(patch1.concat(patch2), a)
// -> a3bc2,true,true
var d = merge[0] // -> a3bc2
```