fixed library book detail in Internet Explorer (XPath lib), see #70

[danielweck]

Pull Request for #70

[danielweck]

Proposed solution in this Pull Request: replace Jath with jQuery.XPath
Caveat: larger-than-needed additional library
Alternative suggestion: let's not use XPath, just parse the OPF metadata "manually"
@ryanackley what do you think?
Note that I initially attempted to fix Jath (to no avail), see comments here:
#70 (comment)

[larsvoigt]

Is your fix working @danielweck? Can your merge this into develop?
It would be awesome the ability to use the book detail in IE. Thanks Lars

[ryanackley]

Sorry this one slipped through the cracks. @danielweck looking at the Jath issue, I think we just need to explicitly create the IE msxml object instead of a DOMParser for the case of IE.

[larsvoigt]

Fast response. I understand not completly the issue :-), but it sounds like you working on it.
Thank you @ryanackley

[danielweck]

@larsvoigt you can use my pull request, but I am somehow reluctant to merge it. The jQuery.XPath library is quite large and complex, compared to Jath. Readium only requires XPath processing to extract metadata from the OPF package file, in the ebook library "info / details pane". A possible alternative would be to parse the OPF metadata without XPath, which would negate the need for an XPath library.

[danielweck]

@ryanackley I didn't try very hard to patch Jath, I just did that:
#70 (comment)
(but as you can see, I gave up when I saw the other IE-related issues in Jath's issue tracker)

Could you please provide some details about the code changes you are suggesting?
Many thanks!

[danielweck]

Interestingly, Readium's current jath-based implementation works fine in Edge, but still breaks in Internet Explorer 11 (latest version on Windows 10).
So, the jxpath-based implementation in https://github.com/readium/readium-js-viewer/tree/feature/libraryBookDetailsIE is only needed for the legacy Trident web browser. Good.

[rkwright]

Defer from 0.22 because this approach is too heavy-handed and needs a rewrite.