Add an optional condition to timer insertions

[lm-sousa]

This condition makes it possible for the inserted timer code to be used only under specified times.

C and C++ insertions tested in Linux with end as undefined and $call.ancestor("scope")

To do:

• Variable declarations still need to be moved outside the scope of the if statements.This will make the code less compact (especially in c++) however it is a necessity for this topology to work.
• [x] C++
• [ ] C Linux
• [ ] C Windows

WARNING: Not tested in Windows. (Windows :vomiting_face: )