Change the name attribute of form elements to accept any string instead of an ID

[jhorstmann]

According to the whatwg html spec the name attribute can be any string:

Other than isindex, any non-empty value for name is allowed

Fixes #40

[jhorstmann]

I went through the "Forms" section of the whatwg spec to verify the affected elements. One notable element is fieldset, the declare macro does not list any attributes at all. I could add the attributes in this PR if wanted.