Embed folly logo in README.md

Summary: References the folly logo from within README.md.

Reviewed By: yfeldblum

Differential Revision: D23490077

fbshipit-source-id: 103c0a7838f9f9982c542e5a82e8382a45d8a0b7

README.md

@@ -5,6 +5,8 @@ Folly: Facebook Open-source Library
 
 ### What is `folly`?
 
+<img src="static/logo.svg" alt="Logo Folly" width="15%" align="right" />
+
 Folly (acronymed loosely after Facebook Open Source Library) is a
 library of C++14 components designed with practicality and efficiency
 in mind. **Folly contains a variety of core library components used extensively