[FIXED JENKINS-25660] - Use hudson.Util methods to tokenize axis values

This method follows the approach in Matrix Project plugin.
In particular, the quoted values won't be splitted to several axis values.

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>
Merge pull request #4 from oleg-nenashev/JENKINS-25660

[FIXED JENKINS-25660] - Use hudson.Util methods to tokenize axis values