Add a little bit to README

README.md

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 # gst
 
-A language and vm.
+GST is a language and vm that is small and embeddable, has metaprogramming
+facilities, can interoperate with C, and has enough features to make it
+a useful general purpose programming language. It is a modern variant of
+Lisp with several native useful datatypes. Some of the more interesting and
+useful features are first class functions and closures, immutable and mutable
+hashtables, arrays, and bytebuffers, macros (NYI), tail-call optimization,
+and continuations (coroutines, error handling). The runtime and bootstrapping
+compiler are written in C99, but should eventually be completely compatible
+with C89 compilers.
+
+As of April 2017, still WIP. While the basic runtime is in place, as are many
+native functions, several important features are still being implemented and
+defined, like continuations and macros. These are also dependant on the
+compiler being ported to gst, which is ongoing. The module system is also not yet
+fully defined.
+
+Currently, there is a repl for trying out the language, as well as the ability
+to run script files. This client program is separate from the core runtime, so
+gst could be embedded into other programs.
+
+## Compiling and Running
+
+Clone the repository and run:
+```sh
+make run
+```
+To build the runtime and launch a repl. The GNU readline library is
+also required for the repl/client, but is not a dependency of the gst runtime.
+
+## Basic programs
+
+To run some basic programs, run the client with one argument, the name of the
+file to run. For example, the client that is built will be located in the
+client directory, so running a program `script.gst` from the project directory
+ would be
+
+```sh
+client/gst script.gst 
+```
+