CFI blacklist (element, class, id)

[danielweck]

Related issue: readium/readium-js-viewer#278

The CFI library currently doesn't expose an API to easily customize blacklists across the board (i.e. for all the features that rely on CFI interpretation/generation). There are functions / methods that take blacklist parameters, but this is not integrated consistently. For example (abbreviated code):

https://github.com/readium/readium-shared-js/blob/develop/js/views/cfi_navigation_logic.js#L544

this.getFirstVisibleElementCfi = function(topOffset) {

        var foundElement = this.findFirstVisibleElement(topOffset);
...
        var cfi = EPUBcfi.Generator.generateElementCFIComponent(foundElement.$element[0]);
...
        return cfi + "@0:" + foundElement.percentY;
    };

Note how EPUBcfi.Generator.generateElementCFIComponent() does not take into account default blacklists, let alone custom ones. Yet, the low-level API itself is capable of handling blacklists:

https://github.com/readium/readium-cfi-js/blob/develop/src/models/cfi_generator.js#L161

generateElementCFIComponent : function (startElement, classBlacklist, elementBlacklist, idBlacklist) {
...
    },

We need a top-level registry of blacklisted elements, classes, ids. There should be a default set (annotation highlights, media overlays character-range highlights, mathjax, etc.), and this should be configurable when the Readium instance is created (allowing vendor customization, e.g. jQuery "highlight" plugin)

[danielweck]

Example of "client side" usage:
https://github.com/readium/readium-shared-js/blob/develop/lib/annotations_module.js#L583

CFIRangeInfo = this.epubCFI.injectRangeElements(
                CFI,
                this.get("contentDocumentDOM"),
                startMarkerHtml,
                endMarkerHtml,
                ["cfi-marker", "mo-cfi-highlight"],
                [],
                ["MathJax_Message"]
                );