naming consistency

Co-authored-by: Nathan Bierema <nbierema@gmail.com>

README.md

@@ -207,7 +207,7 @@ Options
 -------
 
 ``` javascript
-var jsondiffpatchInst = require('jsondiffpatch').create({
+var jsondiffpatchInstance = require('jsondiffpatch').create({
     // used to match objects when diffing arrays, by default only === operator is used
     objectHash: function(obj) {
         // this function is used only to when objects are not equal by ref