Finalize 1.3

[henryiii]

Here are a few things that should be finished before the 1.3 release is ready:

• Extras help message should be improved (simple print)
• Check other help messages (simple print)
• Check that -e number fails if number is missing (critical)
• Try to move most string output in errors to error definitions (easier localization)
• Revisit locking required(), remove checks from (most) individual lambdas, new error if wrong number given
• Consider changing default for take_last; since git uses take_last it is probably a more common default: Added policies instead