use strict

needed by newer versions of jshint that are accepted by package.json.
first part of upgrade to grunt 0.4.
make test pass

replace draft test with one that shows
expansion does take place.
avoid grunt.file.expandFiles

this is subsumed by grunt.file.expand with filter
in grunt-0.4.
replace registerHelper with require

The registerHelper API is gone in grunt-0.4
deleted bin/grunt-markdown

This relied on grunt.npmTasks, an API intended for global installs,
which is gone in grunt-0.4
upgrade to grunt-0.4

adapt for new grunt.js name and config.
upgrage dependency in package.json
adapt README.md for grunt-0.4
adapt package.json

 * bin/grunt-markdown no longer provided, dont list it in package.json
 * package.json test script should now invoke grunt nodeunit
Merge pull request #4 from ekonijn/upgrade-grunt-0.4

Upgrade grunt 0.4