fix image path

readme.markdown

@@ -4,7 +4,7 @@
 
 tinyusb is an open-source (BSD-licensed) USB Host/Device/OTG stack for embedded micro-controller. It is developed using [Test-Driven Development (TDD)](tests/readme.md) approach to eliminate bugs as soon as possible.
 
-![tinyusb diagram](/docs/images/what_is_tinyusb.png)
+![tinyusb diagram](http://docs.tinyusb.org/images/tinyusb_overview.png)
 
 ## Features ##
 

tests/readme.md

@@ -15,5 +15,4 @@ Continuous Integration (CI) is used to automatically run all the tests whenever
 
 As many other open source project, tinyusb uses Travis-CI server (free for OOS). You can find my project on Travis here https://travis-ci.org/hathach/tinyusb  
 
-<!-- https://travis-ci.org/hathach/tinyusb --> 
-[![Build Status](https://travis-ci.org/hathach/tinyusb.png?branch=master)](https://travis-ci.org/hathach/tinyusb)
+[![Build Status](https://travis-ci.org/hathach/tinyusb.svg?branch=master)](https://travis-ci.org/hathach/tinyusb)