Support customized order of plugins

[aleen42]

No description provided.

[aleen42]

To implement this feature, we may need to split the image.svg

[lowlighter]

Yes it requires a bit more work and testing, but it's actually a nice idea.

I still have #48 pending so I'd like to merge it before starting a split of image.svg but should be finished today.
As for the split I may handle it since it's a bit touchy, but after that you should be able to rebase your pr and reopen it.

Or I can do implement the plugins_order in the same time, as you want.

[lowlighter]

Implemented in #53