Add rudimentary README

README.md

+# Master's Thesis
+
+In the absence of a project name: This is my master's thesis
+
+## Building
+
+    stack build
+
+## Running
+
+There isn't much to see, yet. To see pretty printed parse results,
+use:
+
+    stack exec ma -- FILENAME
+
+Where FILENAME is a yaml file describing the input. There is an
+example in `examples/example.yaml`.