Move ExistsAndIsVisible from IPageReader to IElementAssert and IWait

[MehdiK]

See below comments

[robdmoore]

It's kind of an assertion really isn't it?

I agree it doesn't make sense to say Read.ExistsAndIsVisible...

[robdmoore]

Should this be WaitFor.VisibleElement(By....)?

[MehdiK]

I think this is an assertion. Perhaps something like AssertThatElements.ExistAndAreVisible()

[robdmoore]

Ah right - yes it is an assertion, but I also had a need the other day for waiting until an element was visible (some JavaScript made an Ajax call and when it finished the element was shown).

[MehdiK]

I definitely think the WaitFor one is quite helpful too. We could use this as a reference to implement a few useful common methods for assertion and waiting.