let the user define which particles to calculate in a separate thread
show the user how to use the Thread option
Bugfix: do not join the thread if no threads available
rename new user option
rename variable
rename function
rename variable
use std::thread instead of boost::thread
catch thread exceptions
use one thread for each pole mass to avoid usage of the user's brain
let the user decide wether to enable threads or not
rename functions to better express what they do