Using tool* attributes on subordinate form control elements

[andruud]

In #22, a <select name=foo toolparameterdescription="Select your foo"> element represents a foo parameter, and we can therefore attach a description to it using toolparameterdescription. But can you do the same for each <option> element within the <select>? Example:

<select name=foo toolparameterdescription="Select your foo">
  <option value="opt1" toolparameterdescription="The cheapest option">Economy Foo</option>
  <option value="opt2" toolparameterdescription="A foo with 8% more legroom">Premium Foo</option>
</select>