Upgrade Timeline diagram trace

There are some ideas to upgrade the current timeline diagram:

• Add option to enable/disable the scale on idle time. => DONE

• Add option to display the trace in a selected duration/ => DONE

• Add a transparent layout that can show the processors label and the label of all tasks.

• When moving the mouse pointer, the time is displayed next to the pointer only when it is located outside an activity => Display time stamp both inside or outside element block.

• When switching from a task to another one, the CPU is not idle, => change color e.g. task switching into gray for all OS.

• The zoom applies to the whole diagram, but just like in GTKWave => Make Zoom online on the X-axis