ps --format: Add config.js doc, fix gofmt, add integration tests

Re-add the docs from @calavera's PR to the moved cli cmd reference docs.
Fix gofmt and vet issues from carried commits
Add integration test for using format with --no-trunc and multi-names
Fix custom_test map order dependency on expected value check
Add docs to reference/commandline/ps.md
Remove "-F" flag option from original carried PR content

Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
Upstream-commit: 542b58d8f7a2ff3b78a71b7d2c3145dd79f1fa97
Component: engine

components/engine/docs/reference/commandline/cli.md

@@ -85,18 +85,26 @@ mechanisms, you must keep in mind the order of precedence among them. Command
 line options override environment variables and environment variables override
 properties you specify in a `config.json` file.
 
-The `config.json` file stores a JSON encoding of a single `HttpHeaders`
-property. The property specifies a set of headers to include in all messages
+The `config.json` file stores a JSON encoding of several properties:
+
+The property `HttpHeaders` specifies a set of headers to include in all messages
 sent from the Docker client to the daemon. Docker does not try to interpret or
 understand these header; it simply puts them into the messages. Docker does
 not allow these headers to change any headers it sets for itself.
 
+The property `psFormat` specifies the default format for `docker ps` output.
+When the `--format` flag is not provided with the `docker ps` command,
+Docker's client uses this property. If this property is not set, the client
+falls back to the default table format. For a list of supported formatting
+directives, see the [**Formatting** section in the `docker ps` documentation](../ps)
+
 Following is a sample `config.json` file:
 
     {
       "HttpHeaders: {
         "MyHeader": "MyValue"
-      }
+      },
+      "psFormat": "table {{.ID}}\\t{{.Image}}\\t{{.Command}}\\t{{.Labels}}"
     }
 
 ## Help