Option parser

[HomesGH]

Describe the bug
There are (at least) two issues with the option parser.

1. The last letters in a long option can be omitted and the option is still valid. E.g. --step=21 is the same as --steps=21 or --final-checkpoin=0 is the same as --final-checkpoint=0.

2. Why is --final-checkpoint an int and not a bool? What does --final-checkpoint=2 mean? If it is boolean, it should (still) work with --final-checkpoint=1|0|True|False.
   

   ls1-mardyn/src/MarDyn.cpp

   Line 49 in 87024df

   op->add_option("--final-checkpoint").dest("final-checkpoint").type("int").metavar("(1|0)").set_default(1).help("enable/disable final checkopint (default: %default)");

To Reproduce
Run any simulation and specify one of the options above.

Expected behavior
It should exit with an error if no valid option is passed.