Added badges to README

Author: vojtechhabarta

README.md

@@ -1,3 +1,7 @@
+[![Maven Central](https://img.shields.io/maven-central/v/cz/habarta/typescript-generator/typescript-generator-core.svg)](https://repo1.maven.org/maven2/cz/habarta/typescript-generator/typescript-generator-core/)
+[![Appveyor](https://img.shields.io/appveyor/ci/vojtechhabarta/typescript-generator/master.svg)](https://ci.appveyor.com/project/vojtechhabarta/typescript-generator)
+[![Stars](https://img.shields.io/github/stars/vojtechhabarta/typescript-generator.svg?style=social)](https://github.com/vojtechhabarta/typescript-generator)
+
 typescript-generator
 ====================
 typescript-generator is a tool for generating TypeScript definition files (.d.ts) from Java JSON classes.