Prefix flags with `disable_`

[adisidev]

cartogram-cpp/src/misc/parse_arguments.cpp

Lines 76 to 80 in 2d00097

	arguments.add_argument("-S", "--simplify_and_densify")
	.help(
	"Boolean: Enable iterative simplification and densification of polygons")
	.default_value(true)
	.implicit_value(false);

For example, in the above code, the flag name is --simplify_and_densify but passing the flag actually disables this action. We should change the title to disable and make the corresponding changes in implicit and default values, and in reading the value like so:

  args.simplify = !arguments.get<bool>("--disable_simplify_and_densify");