New implementation disscussed on issue #4

"And" and "Or" method accepts VerbalExpression objects. This allows very
complexe expressions to be built sequencially
Reactivate TestOrMethod
Unefficient concatenation fixed
Add a fake "Not" implementation

This is not exactly the same as "?!" in PCRE. At this time we fake the
negative search using:
Not("value") => (?:[^v]|v[^a]|va[^l]...)

That means:
find not "v", or "v" and not "a", or "va" and not "l", and so on...
Append documentation
Merge pull request #27 from metal3d/fake-not-implementation

Fake not implementation + Or enhancments