Update README.md

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README.md

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-# SWE_HW_0
-first/test project for SWE
+# Highlighter
+
+Highlighter is a small tool that highlights
+leaf level GUI-components in an Android application screenshot by
+parsing and processing xml files, thus making it easier for
+developers to understand the GUI. 
+
+## Usage
+Place the program file in the same folder as the xml files and the corresponding screenshots (in png format). Make sure that the xml files and the png files share the same name. 
+
+Compile and run the program using
+
+```bash
+python highlighter.py
+```
+
+The program will run on all xml files in the folder. If it encounters an error in an xml file, or cannot find a matching png, that file will be skipped.
+
+Annotated PNG results will be saved to the same folder that the program is in.