reasonable defaults

[jasonkarns]

Related to #2, wouldn't it make sense to make most of these options true by default? I could understand making certain options default to false (specifically those which might be considered a bit extreme). But to have all options default to false makes the grunt task completely ineffectual out of the box.

[yaniswang]

Use default ruleset when options is undefined:

htmlhint: {
  all: {
    src: ['*.html']
  }
}

What do you think?

[jasonkarns]

Grunt has built-in facilities for setting defaults. Would you rather I submit a PR?

[yaniswang]

Ok, please submit PR.