Make 'info' output yamllint compatible

[dominikl]

Fixes #19

Makes the 'info' command output yamllint compatible.

Test:
./omero render info --style yaml Image:123 > test.yml
Then yamllint test.yml shouldn't report any errors/warnings.

[sbesson]

Using this branch, tested against a public IDR image

(render) sbesson@ls30630:render $ ~/Downloads/OMERO.py-5.4.7-ice36-b93/bin/omero login public@idr.openmicroscopy.org
ERROR:omero.gateway:No Pillow installed, line plots and split channel will fail!
Password:
Created session for public@idr.openmicroscopy.org:4064. Idle timeout: 10 min. Current group: Public
(render) sbesson@ls30630:render $ ~/Downloads/OMERO.py-5.4.7-ice36-b93/bin/omero render info  Image:4007801
ERROR:omero.gateway:No Pillow installed, line plots and split channel will fail!
Using session for public@idr.openmicroscopy.org:4064. Idle timeout: 10 min. Current group: Public
rdefv1: model=color, z=494, t=265
tiles: False
ch0: active=True,color=00FF00,label=H2B-eGFP,min=0.0,start=0.0,end=1093.0,max=65535.0
ch1: active=True,color=FF0000,label=myr-tdTomato,min=0.0,start=0.0,end=439.0,max=65535.0

(render) sbesson@ls30630:render $ ~/Downloads/OMERO.py-5.4.7-ice36-b93/bin/omero render info  Image:4007801 --style yaml
ERROR:omero.gateway:No Pillow installed, line plots and split channel will fail!
Using session for public@idr.openmicroscopy.org:4064. Idle timeout: 10 min. Current group: Public
---
channels:
    1:
        active: true
        color: 00FF00
        end: 1093.0
        label: H2B-eGFP
        max: 65535.0
        min: 0.0
        start: 0.0
    2:
        active: true
        color: FF0000
        end: 439.0
        label: myr-tdTomato
        max: 65535.0
        min: 0.0
        start: 0.0
greyscale: false
t: 266
version: 2
z: 495
(render) sbesson@ls30630:render $ ~/Downloads/OMERO.py-5.4.7-ice36-b93/bin/omero render info  Image:4007801 --style yaml > out.yml
ERROR:omero.gateway:No Pillow installed, line plots and split channel will fail!
Using session for public@idr.openmicroscopy.org:4064. Idle timeout: 10 min. Current group: Public
(render) sbesson@ls30630:render $ bin/yamllint out.yml 
(render) sbesson@ls30630:render $ cat out.yml 
---
channels:
    1:
        active: true
        color: 00FF00
        end: 1093.0
        label: H2B-eGFP
        max: 65535.0
        min: 0.0
        start: 0.0
    2:
        active: true
        color: FF0000
        end: 439.0
        label: myr-tdTomato
        max: 65535.0
        min: 0.0
        start: 0.0
greyscale: false
t: 266
version: 2
z: 495
(render) sbesson@ls30630:render $ ~/Downloads/OMERO.py-5.4.7-ice36-b93/bin/omero render info  Image:4007801 --style json
ERROR:omero.gateway:No Pillow installed, line plots and split channel will fail!
Using session for public@idr.openmicroscopy.org:4064. Idle timeout: 10 min. Current group: Public
{"channels": {"1": {"end": 1093.0, "min": 0.0, "color": "00FF00", "max": 65535.0, "label": "H2B-eGFP", "start": 0.0, "active": true}, "2": {"end": 439.0, "min": 0.0, "color": "FF0000", "max": 65535.0, "label": "myr-tdTomato", "start": 0.0, "active": true}}, "greyscale": false, "version": 2, "z": 495, "t": 266}

As opposed to

(omeropy) sbesson@ls30630:~ $ ~/Downloads/OMERO.py-5.4.7-ice36-b93/bin/omero render info  Image:4007801 --style yaml > /tmp/out.yml
ERROR:omero.gateway:No Pillow installed, line plots and split channel will fail!
Using session for public@idr.openmicroscopy.org:4064. Idle timeout: 10 min. Current group: Public
(omeropy) sbesson@ls30630:~ $ ~/venvs/flake8/bin/yamllint /tmp/out.yml 
/tmp/out.yml
  1:1       warning  missing document start "---"  (document-start)
  2:81      error    line too long (88 > 80 characters)  (line-length)
  3:5       error    wrong indentation: expected 6 but found 4  (indentation)
  4:81      error    line too long (81 > 80 characters)  (line-length)
  5:5       error    wrong indentation: expected 6 but found 4  (indentation)
  7:1       error    too many blank lines (1 > 0)  (empty-lines)

(omeropy) sbesson@ls30630:~ $ cat /tmp/out.yml 
channels:
  0: {active: true, color: 00FF00, end: 1093.0, label: H2B-eGFP, max: 65535.0, min: 0.0,
    start: 0.0}
  1: {active: true, color: FF0000, end: 439.0, label: myr-tdTomato, max: 65535.0,
    min: 0.0, start: 0.0}
greyscale: false

with the current version.

I have extensions to the info --style integration tests to compare the output but I propose to merge this and open as a follow-up PR before cutting a patch release unless you would rather combine the code and the tests here.

[sbesson]

Now released as https://pypi.org/project/omero-cli-render/