Update Grunt instruction links and wording

[nschonni]

• Replace "Requires" with "Uses" since these aren't external dependencies that are installed outside of 'npm install'
• Add additional project links for QUnit and JSHint
• Use placeholders for 'recess' and UglifyJS since they are linked multiple times. Also use there project pages instead of the GH repos to be consistent with links like Jekyll and Grunt earlier in the document

[cvrebert]

I'd prefer to retain the "Requires" phrasing. It hammers the point home.
Also, phantomjs really does need to be installed manually by the user.

[nschonni]

grunt-contrib-qunit uses https://npmjs.org/package/grunt-lib-phantomjs so you don't need a host install

[nschonni]

I'd get the "Requires" phrasing for stuff like grunt-contrib-sass which requires Ruby and Gems installed separately

[cvrebert]

Huh, guess I haven't looked that closely at the phantomjs stuff since the switch to Grunt.

[cvrebert]

Alrighty then. Thanks.

[nschonni]

Thanks for landing 👍
I think the npm-able PhantomJS only came along with Grunt 0.4, plus it's pretty well hidden inside there lib repos 😄