update changelog/credits and bump to version 4.2.0

switch to version 4.1.0

switch to version 4.0.0

switch to version 3.1.1

switch to version 3.1.0

switch to version 3.0.1

switch to version 3.0.0

switch to version 2.14.3

switch to version 2.14.2

refactor the help page slightly

put all the option help tags in single quotes