Updated ROADMAP

I now plan to use a simple, cross-platform system to run tests,
instead of using a different library for each platform (i.e. QUnit
for the browser, Jasmine for Node.js, ...)

As a consequence, I updated the ROADMAP to move examples and tests
running in Node.js to the next step.
Simplify EXAMPLES section in README

The examples are now based on the definition of a log() function
based on console.log(), which is more familiar than assert() and
unit tests for JavaScript developers.
Move log module example to browser/ subdirectory

This example module, logging to a DOM element retrieved with
document.getElementById(), is meant to run in the browser
environment.

I will put a copy of the log module defined in the EXAMPLES
section of the README in its place.
Add module to alias console to the context in examples
Add log module to examples (from EXAMPLES section of README)
Concatenate arguments to console.log()

In Node.js, separated string arguments are surrounded with single quotes.
I updated the code of the example to concatenate the timestamp with the
message instead, to get the same result as in the browser.
Use | as separator between timestamp and message in log()
Add examples for Node.js

I moved the modules to the folder 'node_modules' to facilitate dynamic
loading in Node.js.

The examples for Node.js are straightforward adaptations of the examples
for the browser, up to the last example, Example 5, which takes a specific
turn: dynamic loading with CommonJS require() in Node.js as opposed to
loading modules in any order (to prepare dynamic loading) in the browser.