adjust line thickness to screen resolution
draw center line in arrow,
add option closing a line (draw line from last to first point), issue #125
simplify code
rename setter, issue #125
add tests for closing the line, issue #125
rename setter, issue #125
improve description, issue #125
add property to close the line to Coordinates class, close #125
don't close line when drawing the arrow lines.
wrap long line
use Math.round
use theme colors for API 14, simple colors for API < 14