Introduce some sort of blacklist/ignorelist for DataURI-plugin

[Schepp]

If someone would like to leave certain images un-datauri-fied, then he/she can put them into this list inside a plugin configuration/options section.

[rodneyrehm]

As we had already discussed for your CSS-JS-Booster:

I would consider not DataURIfying any image that appears more than once. This would reduce configuration overhead significantly.

[commi]

there is already a size-limit for data-uris (24kb), which should be made configurable.

but the datauri-plugin would have to be (totally?) rewritten as i see it to detect duplicate usage of images. if it could, you would just have to apply the size-limit to filesize*filecount and the latency/bandwith-tradeoff would always be optimal.