Fix reading time at t=t final

When reading the particles, I am always opening 2 index files. One before the requested time and one after (for the history). Currently, if you are asking for the final time, the code will open the last index file and will try with the "next" one. Therefore I need to add a special case for the final time.

Fix #739 (closed)

changed milestone to %Continuous Simulation Data Stream

added bug label

changed the description

merged

mentioned in commit d2b5e59c