Duplicated DOM queries: take context into consideration

Resolves #395

```
Offenders for DOMqueriesById (6):
 * #foo (in #document)
 * #foo (in #document)
 * #delete (in #document)
 * #foo (in #document)
 * #list1 (in #document)
 * #list2 (in #document)

Offenders for DOMqueriesByClassName (1):
 * .bar (in #document)

Offenders for DOMqueriesByTagName (7):
 * * (in div)
 * script (in DocumentFragment > b[0])
 * script (in DocumentFragment > b[0])
 * * (in body > span#delete)
 * span (in #document)
 * li (in body > ul#list1)
 * li (in body > ul#list2)

Offenders for DOMqueriesByQuerySelectorAll (1):
 * #foo (in #document)

Offenders for DOMinserts (2):
 * "div" appended to "html"
 * "DocumentFragment > b[0]" appended to "body > p#foo"

Offenders for DOMqueriesDuplicated (2):
 * id "#foo" (in #document): 3 queries
 * tag name "script" (in DocumentFragment > b[0]): 2 queries
```