Suppressed warnings
Change computation of bounds for window/level (handle negative values)
Change composite param to use QHash to set values (was buggy before)
Remove useless qdebugs
Solves the problem of window level using the sliders with images having small value ranges
Window limited to 0 everywhere
Correct number of decimals shown based on current step
Correct WL transmission bug between 3d and 2d view
Added some comments to justify the use of (void), and cleaned-up some commented code
Merging fcollot:remove-warning, closes PR #148
Correct zooming bug in 3d mode
Levels are not constrained by image values anymore
Merge pull request #157 from ocommowi/wl-composite-bug-correction

WL composite bug correction
time is now managed by the navigator, interactor have the responsbility to update the sequence being view.
TimeLine is now managed only by the navigator. it is updated accordingly to the data in the view rely on metaData.
intercator for 4d mesh now inherit from 3d mesh.
Remove old declaration in vtkDataMesh4DInteractor and force update of the view when one call medVtkView::update (by calli,g Modified on view2/3d.)
One QTimeLine to rule them all.
Fix timeLine alwas visible issue.
updates the total number of frame label when layer added/removed