Xml validator script

When writing `.xml` files for the parameter-framework, it is common to make mistakes

In order to check the *validity* of the xml files, the parameter-framework is using Schemas files.
Instead of restarting `remote-process` and `test-platform`, the validity can be checked with the `xmlValidator.py` script
code blocks must be on a paragraph of their own in order to be considered as such.  This does not look right in the redered version.