Add --format support to images command

- rename `api/client/ps` to `api/client/formatter`
- add a a image formatter

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

docs/reference/commandline/cli.md

@@ -103,6 +103,12 @@ 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.md)
 
+The property `imagesFormat` specifies the default format for `docker images` output.
+When the `--format` flag is not provided with the `docker images` 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 images` documentation](images.md)
+
 Following is a sample `config.json` file:
 
     {
@@ -110,6 +116,7 @@ Following is a sample `config.json` file:
         "MyHeader": "MyValue"
       },
       "psFormat": "table {{.ID}}\\t{{.Image}}\\t{{.Command}}\\t{{.Labels}}"
+      "imagesFormat": "table {{.ID}}\\t{{.Repository}}\\t{{.Tag}}\\t{{.CreatedAt}}"
     }
 
 ### Notary

docs/reference/commandline/images.md

@@ -177,3 +177,53 @@ In this example, with the `0.1` value, it returns an empty set because no matche
 
     $ docker images --filter "label=com.example.version=0.1"
     REPOSITORY          TAG                 IMAGE ID            CREATED              VIRTUAL SIZE
+
+## Formatting
+
+The formatting option (`--format`) will pretty print container output
+using a Go template.
+
+Valid placeholders for the Go template are listed below:
+
+Placeholder | Description
+---- | ----
+`.ID` | Image ID
+`.Repository` | Image repository
+`.Tag` | Image tag
+`.Digest` | Image digest
+`.CreatedSince` | Elapsed time since the image was created.
+`.CreatedAt` | Time when the image was created.
+`.Size` | Image disk size.
+
+When using the `--format` option, the `image` command will either
+output the data exactly as the template declares or, when using the
+`table` directive, will include column headers as well.
+
+The following example uses a template without headers and outputs the
+`ID` and `Repository` entries separated by a colon for all images:
+
+    $ docker images --format "{{.ID}}: {{.Repository}}"
+    77af4d6b9913: <none>
+    b6fa739cedf5: committ
+    78a85c484f71: <none>
+    30557a29d5ab: docker
+    5ed6274db6ce: <none>
+    746b819f315e: postgres
+    746b819f315e: postgres
+    746b819f315e: postgres
+    746b819f315e: postgres
+
+To list all images with their repository and tag in a table format you
+can use:
+
+    $ docker images --format "table {{.ID}}\t{{.Repository}}\t{{.Tag}}"
+    IMAGE ID            REPOSITORY                TAG
+    77af4d6b9913        <none>                    <none>
+    b6fa739cedf5        committ                   latest
+    78a85c484f71        <none>                    <none>
+    30557a29d5ab        docker                    latest
+    5ed6274db6ce        <none>                    <none>
+    746b819f315e        postgres                  9
+    746b819f315e        postgres                  9.3
+    746b819f315e        postgres                  9.3.5
+    746b819f315e        postgres                  latest