REFACTORING: corrected the name for test "step_plot_per_series"
BUGFIX #451: fixed "connect-separated-points" bug
TEST: adapted test for bugfix
REFACTORING: use the method "getLeftBoundary" instead of a private
variable
BUGFIX: bugfix for issue #451 is now also working for bars
FEATURE: extended test for the bugfix for issue #451
EXAMPLE: added new example for fixed bug
REFACTORING: adapted EOL
REFACTORING: fixed jslint violation