Fix some bugs in replay

[TheBEber]

• Adapting replay speed to recorded scenario
• Concatenation of TimeElapsed cannot be done as proposed, need to be splitted after another event (to be able to calculate the time during which a button has been pressed, and replay it exactly) (exemple of a jump, when we start/stop pushing a button needs to be exact, in the exemple in the commit message, we may consider the button has been pressed for twice the real time (repends of the implementation for sure...))
• Gui start state needs to be recorded (windows size/scale & position of internal elements -> saved for now in imgui.ini, but needs to be reset to the state before the start of recording in order to replay it correctly) ( this commit may not be the good way to handle it, but it is more for illustration of the problem)
• Some bug still exists : mouse clic does not seems to work for windows resize (Resize event to be handled) and internal sub-windows movement/resizing does not seems to work either