Modified some constrains to works on iOS8 and iPhone6. closes #396

the constraints used on FeedbackViewController (with some smoothly managed exceptions) and EditTimeEntryViewController works better.
fixes #396
the solution I was working was related with this constraints.. I created both and then, in order to animate the layout, I was trying to change the constant parameter of the constraints and update the layout inside the animation block. 

http://stackoverflow.com/questions/12622424/how-do-i-animate-constraint-changes

The layout is broken if you remove it ( RemoveConstraints method)