Add README.md files for moterm and moterm_example_app.

examples/moterm_example_app/README.md

+# Moterm example application
+
+`moterm_example_app` is an example application that embeds
+[Moterm](../../apps/moterm), uses it to provide a prompt, and allows it to be
+connected to other applications (which should implement the
+`mojo.terminal.TerminalClient` interface).
+
+## Running
+
+On Linux, run it in the usual way, e.g.:
+
+    $ mojo/devtools/common/mojo_run --enable-multiprocess "mojo:window_manager mojo:moterm_example_app"
+
+You'll probably need to click on the window to give it keyboard focus. You may
+also want to resize the window (especially horizontally) to make it bigger.
+
+At the `:)` prompt, you may enter the URL for any application implementing the
+`mojo.terminal.TerminalClient` interface. E.g.:
+
+    :) mojo:dart_netcat
+
+At this point, the terminal's input/output is transferred to the specified
+application. In this case, it just outputs a help message and closes the
+terminal, returning you to the `:)` prompt. You may also try:
+
+    :) mojo:dart_netcat?localhost&port=80
+
+In this case, `mojo:dart_netcat` will make a TCP connection to the specified
+host/port. Assuming you have a web server running on your machine, you may try
+entering:
+
+    GET /
+
+(It's probably a bug in `mojo:dart_netcat` that it doesn't close the terminal
+"file". You can press Control-D to return to the `:)` prompt. The unhandled Dart
+exception after you press Control-D is definitely a bug.)
+
+Another example you may try is:
+
+    :) file:///path/to/src/examples/js/repl.js
+
+At its `>` prompt, you can enter JavaScript expressions. E.g.:
+
+    > function add(x, y) { return x + y; }
+    undefined
+    > add("hello ", 123)
+    "hello 123"
+
+## See also
+
+* [//apps/moterm](../../apps/moterm)
+* [//examples/dart/netcat](../dart/netcat)
+* [//examples/js/repl.js](../dart/js/repl.js)