We are planning to allow things like freezing the calendar, which
makes this variable a bit problemetic. So instead, suggest to the
user how many ticks there are in a calendar day, and let them figure
out how many ticks they want.
Additionally, use a TimeoutTimer for this, instead of an end-date
variable which is checked in an IntervalTimer.
This to prevent compilation issues between runs with and without precompiled
headers. Also remove the headers from the rest of the code base as they are
not needed there anymore, although they do relatively little harm.