Fix clover formatter

[ale7714]

Clover formatter was expecting coverage data to look like:

<coverage generated="11111">
  <project timestamp="111111">
    <package>
      <file name="path1">
        <line num="23" type="stmt" count="0"/>
      </file>
      <file name="path2">
        <line num="2" type="stmt" count="0"/>
      </file>
    </package>
  </project>
</coverage>

But a valid syntax is to also have files without the package tag wrapping them, like this:

<coverage generated="11111">
  <project timestamp="111111">
    <file name="path1">
      <line num="23" type="stmt" count="0"/>
    </file>
    <file name="path2">
      <line num="2" type="stmt" count="0"/>
    </file>
  </project>
</coverage>

This PR adds supports for that

[dblandin]

Looks pretty good to me. Just a general comment that it's difficult to review unfamiliar code when all of the variables are one or two letter abbreviations.

Maybe we can flesh out these variable names so the code is easier to digest?

[ale7714]

@dblandin completely agree. Being making a conscious to use better var names.