add failing test for desired functionality in james.watch

This commit adds tests for the following unimplemented ways of using
james.watch:

    // Run the named task when the watched file changes
    james.watch('test/**/*.js', 'foo');

    // Run the listed tasks when the watched file changes
    james.watch('test/**/*.js', ['foo', 'bar']);
implement shorthand forms for james.watch

This implements the following two shorthand forms for james.watch:

    // Run the named task when the watched file changes
    james.watch('test/**/*.js', 'foo');

    // Run the listed tasks when the watched file changes
    james.watch('test/**/*.js', ['foo', 'bar']);
Merge pull request #16 from japsu/watch_improvement

Shorthand forms for james.watch