Added license badge to Readme file.

Readme.md

@@ -22,6 +22,7 @@ Direct and inverse location can be used to perform full ortho-rectification of
 images and correlation between sensors observing the same area.
 
 
+[![](http://img.shields.io/:license-apache-blue.svg)](http://www.apache.org/licenses/LICENSE-2.0.html)
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