Add a new TimelineEvent.h not to pull chrono in Algorithm.h

Algorithms are not very quick to compile, in particular functional algorithms. This change doesn't pull chrono, which is a heavy header, in Algorithm.h, meaning it won't be pulled in algorithms unless there is something else that needs it. With this change I have picked a couple of algorithms and compilation is reduced by 0.3s on a very fast machine, possible more on a slower one.