Singleton for WebDriverUtils

[white-sdev]

Implement a Singleton or make the methods static for simplicity for the user.

[white-sdev]

In version 0.1.0 a new TestCase structure was implemented and although a singleton wasn't created its usefulness is not the same, it will be nice to have the structure in case of needed though.

[obed-vazquez]

I think this issue is obsolete at this point, I don't see how a Singleton will help the structure.