On Windows, when in the registry, os.Getwd() returns the previous
path rather than the registry location. Settings PWD as an environment
variable might seem hacky but it's the only way to resolve this.
Resolves#40
only display UserInfoSeparator if both username and hostname are dislayed
cleanHostName only if it ends with garbage instead of contains.
fixes .localdomain having just .local stripped
add .localdomain to garbage