Update Python instructions, add simple testsuite (which fails with segmentation fault)

src/runtime/python/README.md

@@ -0,0 +1,19 @@
+# Python bindings to C runtime
+
+## Pre-requisites
+
+1. You must have installed the PGF C runtime (see `../c/README.md`)
+2. You will need the system Python development package, e.g.:
+  - RedHat: `yum install python-devel`
+  - Debian: `apt install python-dev`
+
+## Installation
+
+```
+$ python setup.py build
+$ sudo python setup.py install
+```
+
+## Usage
+
+See `examples/`.