Fix <label for="checkbox">

[denilsonsa]

The HTML <label> element can have an optional attribute for, which should be set to the id of the respective input element.

<input type="checkbox" id="foobar">
<label for="foobar">Foo bar</label>
<!-- Note: the type here does not matter, it works for all types. -->

Alternatively, the <input> element can be put inside the <label> element.

<label for="foobar"><input type="checkbox" id="foobar"> Foo bar</label>

I've noticed this issue in:

• https://github.com/anthonynosek/sprint-reader-chrome/blob/master/src/advanced.html
• https://github.com/anthonynosek/sprint-reader-chrome/blob/master/src/reader.html
• Maybe other HTML files.

[anthonynosek]

Thanks Denilson. I have tidied up ALL the elements to ensure they have a corresponding "for" attribute where required. This will be released in version 2.1.