[IMP] website: image controller can use xmlid
Merge pull request #2153 from odoo-dev/master-website-image-controller-chm

[IMP] website: image controller can use xmlid
[IMP] mail: chatter: Send message / Log a note tooltips improvements, to better explain to the user why the world is about to collapse into a molecular singularity.
[FIX] web_tip: don't display tip on element whose width or height is 0

This commit allows a tip to be properly displayed on elements containing
an img tag. Previously the tip would be displayed before the image could
be loaded, thus breaking the ui.
[IMP]Website Blog: Make Onboarding tour user friendly and change customize cover feature

[IMP]Website Blog: Make Onboarding tour user friendly and change customize cover feature