Merge pull request #3 from golib/feature/go-mod

What: bomb to v1.4.0

Merge pull request #2 from golib/flag-slice

What: slice flag issue

What: remove urfave/cli dependence

Why:

  * separate from urfave/cli

How:

  * nop

Merge pull request urfave#108 from modcloth/env-config-fun

Adding support for default from the env

Merge pull request urfave#112 from AudriusButkevicius/swap

Add Args.Swap command for swapping arguments

Update README.md

Added API docs url