Convenience funcs for `some_option.unwrap_or(...)`
Convenience funcs for `some_option.unwrap_or(...)`

This ensures consistent handling of default values for options that are
None if not specified on the command line.

graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust