Use H for host option short flag. (#247)
Use H for host option short flag. (#247)

Fixes subcommand help display (`-h`).
Add program help text to show subcommand help.
chiedo/gatsby,ChristopherBiscardi/gatsby,okcoker/gatsby,fk/gatsby,0x80/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,rothfels/gatsby,fabrictech/gatsby,Khaledgarbaya/gatsby,gatsbyjs/gatsby,fk/gatsby,danielfarrell/gatsby,gatsbyjs/gatsby,mickeyreiss/gatsby,ChristopherBiscardi/gatsby,mingaldrichgan/gatsby,fabrictech/gatsby,fabrictech/gatsby,gatsbyjs/gatsby,Khaledgarbaya/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby,chiedo/gatsby,mingaldrichgan/gatsby,chiedo/gatsby,mickeyreiss/gatsby,Khaledgarbaya/gatsby,fk/gatsby,danielfarrell/gatsby,okcoker/gatsby,ChristopherBiscardi/gatsby,0x80/gatsby,mickeyreiss/gatsby,rothfels/gatsby,danielfarrell/gatsby,mingaldrichgan/gatsby,okcoker/gatsby