CB-9782 Implements PlatformApi contract for Android platform.

This closes #226

node_modules/shelljs/src/echo.js

@@ -0,0 +1,20 @@
+var common = require('./common');
+
+//@
+//@ ### echo(string [,string ...])
+//@
+//@ Examples:
+//@
+//@ ```javascript
+//@ echo('hello world');
+//@ var str = echo('hello world');
+//@ ```
+//@
+//@ Prints string to stdout, and returns string with additional utility methods
+//@ like `.to()`.
+function _echo() {
+  var messages = [].slice.call(arguments, 0);
+  console.log.apply(this, messages);
+  return common.ShellString(messages.join(' '));
+}
+module.exports = _echo;