Update README to reflect the addition of the compiler.

README.md

@@ -1 +1,15 @@
-License: MIT license.  A more detailed README will follow.
+Lithium is an attempt at several things at once:
+
+ * An assembler for x86 CPUs, written in Clojure and using
+   Clojure S-expressions as its input data. This part has been
+   first announced in [this blog post][1].
+ * A compiler for a toy Lisp-like language, using that assembler as a
+   backend. The compiler is being written following the guidelines
+   found in a paper "[An Incremental Approach to Compiler Construction][2]."
+
+The purposes of Lithium are, first and foremost, to learn and to have fun. 
+
+License: MIT.
+
+ [1]: http://blog.danieljanus.pl/130656082
+ [2]: http://scheme2006.cs.uchicago.edu/11-ghuloum.pdf