Add xml option to fix command for NetBeans IDE support
merged branch junichi11/fix-result-as-xml (PR #211)

This PR was squashed before being merged into the master branch (closes #211).

Discussion
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Add xml option to fix command for NetBeans IDE support

We (NetBeans PHP developer and me) would like to add support for PHP CS Fixer to NetBeans IDE (after version 7.4).
If we can get results for fix command as xml, we can use results easily.
So, I tried to add xml option. But my changes would have some problems. (e.g. diff result contains "<info>", "<error>".)

Could you add improvements like this?
Thanks.

Commits
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9a54bff Add xml option to fix command for NetBeans IDE support