Implement support for using phpunit.xml files

[dawehner]

Solves #156

[codecov-io]

Current coverage is 3.72%

Merging #157 into master will decrease coverage by 0.29%

@@            master      #157   diff @@
========================================
  Files           13        13          
  Lines          498       537    +39   
  Methods         44        46     +2   
  Messages         0         0          
  Branches         0         0          
========================================
  Hits            20        20          
- Misses         478       517    +39   
  Partials         0         0          

Powered by Codecov. Last updated by 4598df6...c297c2e

[localgod]

Thanks for the pull request. Support for phpunit.xml files is a valuable addition.
I can not seem to activate your addition no mater where I put my phpunit.xml file. Could you expand your pull request by adding a sample setup? I would expect vpu to parse a phpunit.xml file located in /tests with below content to exclude ExpectedFailureTest.php however this dos not seem to happen.
`

<testsuites>
    <testsuite name="VisualPhpUnit test suite">
        <directory>./</directory>
        <exclude>./ExpectedFailureTest.php</exclude>
    </testsuite>
</testsuites>

`
Could also be I have misunderstood how your code should work.

[localgod]

Closing this one as there has been no follow up for some time.