rust example working, clean up

.gitignore

@@ -1,3 +1,4 @@
 /venv
 /frames
 **/*.png
+thermaldecoder/target

README.md

@@ -1,3 +1,15 @@
 ### Thermal decoder
 
 https://wiki.telavivmakers.org/tamiwiki/projects/thermalcam
+
+
+### Rust lib usage
+
+# if you don't already have a virtualenv. Linux specific, adjust to your OS.
+```bash
+virtualenv venv
+. venv/bin/activate
+pip install -r requirements.txt
+(cd thermaldecoder; maturin develop -r)
+python test_rust.py
+```