* adds new flag `-y` prompting for user confirmation before removal
* Modified existing integration tests to work with the fix#2349.
* Added tests for checking user confirmation, updated the test cases use sub-shell with `|`
* Updated the reference docs for rm sub-command
incorporated changes by @dgageot, @jeanlaurent and @nathanleclaire
Signed-off-by: Anil Belur <askb23@gmail.com>
Splitting out docs
Fixing location of help
entering in changes from testing
Filling in some missing structure
Updating with the comments from Nathan
Updating with the comments from Nathan
Updating after talk with Evan/Nathan
Signed-off-by: Mary Anthony <mary@docker.com>
