cli: Use docker term package for run

This properly handles making the terminal raw, which allows terminal
control like ^C to work properly.

Signed-off-by: Jonathan Rudenberg <jonathan@titanous.com>
Godeps: Remove unused github.com/heroku/hk/term package

Signed-off-by: Jonathan Rudenberg <jonathan@titanous.com>
pkg/exec: Remove spurious finished checks

finished is set as soon as Wait is called.

Signed-off-by: Jonathan Rudenberg <jonathan@titanous.com>
host/cli: Add run command to run interactive jobs

Signed-off-by: Jonathan Rudenberg <jonathan@titanous.com>