Switch "printHelp" tabwriter padchar to space
Switch "printHelp" tabwriter padchar to space

Using tabs for alignment is troubling if the output is used for anything besides display in a terminal (or if the user's terminal allows for adjustment of the default tab size), as noted by the documentation for `tabwriter` (https://golang.org/pkg/text/tabwriter/#Writer.Init):

> (for correct-looking results, tabwidth must correspond to the tab width in the viewer displaying the result)

The safer solution is to use `' '` as the `padchar`, which only carries the assumption of a fixed-width font (which is a more reasonable assumption than a fixed, constant tab size).

murdinc/cli,ykanda/cli,urfave/cli,minio/cli,murdinc/cli,cmars/tools,pjvds/cli,phinnaeus/cli,urfave/cli,cmars/tools,ykanda/cli,codegangsta/cli,cmars/tools,phinnaeus/cli,minio/cli,pjvds/cli,codegangsta/cli,murdinc/cli,cmars/tools,ykanda/cli,pjvds/cli,minio/cli,phinnaeus/cli