fix/implement multiline legend

Proper implementation of multiline legends
Adaption and renaming of the testcase "one_point" to "multiline_labels"

Tested in R2014a and R2014b

Unfortunately in R2014a the line `legendString = get(child, 'DisplayName');` in `findLegendInformation` has issues with multiline fields. A legend with `{'ab','cd'}` is read out as `acbd`. 
`legendString = reshape(legendString,2,length(legendString)/2)` would properly reorder the characters.
I consider this a bug and outside the scope of this pull request.
@egeerardyn How should we handle this?
Unfortunately it doesn't :-1: I tried that today... The `cellfun`-approach also isn't feasible due to the loop's large content. A nested loop for both possible dimensions of the cell would be possible, though I didn't quite like it. hmm...