Environment for learning programming using mu: http://akkartik.name/post/mu
Run it from the mu directory:
```shell
$ ./mu edit
```
This will load all the `.mu` files in this directory and then run the editor.
Press ctrl-c to quit. Press F4 to save your work (if a lesson/ directory
exists) and to run the contents of the sandbox editor on the right.
You can also run the tests for the environment:
```shell
$ ./mu test edit
```
You can also load the files more explicitly by enumerating them all:
```shell
$ ./mu edit/*.mu
```
This is handy if you want to run simpler versions of the editor so you can
stage your learning.
```shell
$ ./mu edit/00[12]*.mu # run a simple editor rather than the full environment
```
To see how the various 'layers' are organized, peek inside the individual
`.mu` files.