added changelog

Author: Sven Ulrich

CHANGELOG.md

@@ -0,0 +1,6 @@
+# CHANGELOG
+
+#### 1.4.0
+- added `AppendLine` and `AppendLineFormat`
+- added hexadecimal conversion specifier
+- bugfix `StringBuilder` initialization without parameter adds empty string.

README-Developers.md renamed to CONTRIBUTING.md

@@ -3,6 +3,9 @@
   "version": "1.4.0",
   "description": "Simple lightweight string operation library for Typescript, works with Angular",
   "main": "dist/index.min.js",
+  "files": [
+    "dist/*"
+  ],
   "scripts": {
     "test": "mocha -r ts-node/register tests/**/tests.ts",
     "build": "gulp default && gulp compress"