Update configurations and package installation documentation

On Plone 4.2 we need to pin plone.app.layout = 2.2.13 to avoid a bug on 'plone.belowcontentbody.relateditems' viewlet
Remove Pillow from dependencies as some people may prefer to use PIL
Update development and CI configurations to use code analysis
Run code analysis after tests to allow failures on validation errors
Update MANIFEST.in