capture rich output as well as stdout/err in capture_output

closes #3742
add outputs property on CapturedIO
add --no-display flag to %%capture

document this new magic in whatsnew, and added docs to the resulting object.
updated Basic Output notebook with  new %%capture
default values for RichOutput attributes
tests for utils.capture
subclass RichOutput in ExecuteReply

they are very similar

add another test for good measure.
Merge pull request #3744 from minrk/capturedisplay

capture rich output as well as stdout/err in capture_output