[Kst] extragear/graphics/kst/tests

[Brisset, Nicolas]

> The skip frames tests currently fail for calculating the nf 
> and f0 in various scenarios.
> 
> It seems my expectations for what skip will do differ from 
> the current implementation.  Consider the given testcase 
> where we have 15 items indexed from 0 to 14.  The RVector is 
> created with nf = -1 (readToEOF), f0 set to 0 (first frame) 
> and a skip value of 5.  I would expect that the result would 
> be a vector with 3 items {0, 5, 10}.  Item #14 does not fit 
> the the skip frame, thus the size of the vector is 3 and the 
> number of frames is 11 (the count of the items between 0 and 
> 10 inclusive).
This is also what I expect. How about f0 = 2 for instance ?