Time control loop with number of iterations

[maierbn]

In a time control loop one can specify start time, end time and time increment. Sometimes this is not desirable, e.g. when I set START_TIME = 0.0_DP END_TIME = 1.0_DP TIME_INCREMENT = 0.1_DP it sometimes performs 11 instead of 10 iterations, because of rounding errors when adding up the time increments. It there would be nice to be able to specify the number of iterations directly.

[maierbn]

The issue is solved by pull request #100