Add a simple version number comparator

refs JENKINS-18727
Add a basic .gitignore file

It itgnores maven's target/ directory and jenkins' maven plugin work/
directory.
Choose the XSL file based on the report version

Starting with cpptest 9.0, the report file format changed slightly,
fortunately the tool version can be found at the same address xml-wise.

This implementation uses a stream reader to avoid completely reading the
report twice: once for the version, and once for the conversion. This is
convenient since the tool version is in the very first element.

The file `cpptestunit-9.0-to-junit-1.0.xsl` isn't actually part of this
commit.

refs JENKINS-18727
Import xslt for cpptest 9.0+ version

Courtesy of Parasoft
Merge pull request #6 from Zenika/cpptest-9.0-support

[JENKINS-18727] Cpptest 9.0+ support