Added a logo to the project. (#277)

* Added a logo to the project.

* Changed the logo from a png to a svg.

README.md

@@ -1,5 +1,13 @@
 # Boa
 
+<p align="center">
+    <img
+      alt="logo"
+      src="./assets/logo.svg"
+      width="30%"
+    />
+</p>
+
 This is an experimental Javascript lexer, parser and compiler written in Rust. Currently, it has support for some of the language.
 [![Build Status](https://travis-ci.com/jasonwilliams/boa.svg?branch=master)](https://travis-ci.com/jasonwilliams/boa)
 [![](http://meritbadge.herokuapp.com/boa)](https://crates.io/crates/boa)