Added handling of MixedList's record IDs as a hidden filter so that c…

[EreMaijala]

…reating a URL or serializing/deserializing the search would work properly. Fixes RSS feeds, emailing the results and saving/removing search for Records/Home action.

Since hidden filters are a standard where params are handled, this is an easy way to persist them in all situations, though not very elegant.

Also added <> around the URL in the email since it prevents the URL from breaking in the email due to length or containing special characters (e.g. Thunderbird breaks on square brackets).

[crhallberg]

Would it better to escape <> as > < or would that cause problems in plain text emails?

[EreMaijala]

It would be wrong in plain text email. Plain angle brackets are a standard way of delimiting a URI in email (see e.g. ftp://ftp.rfc-editor.org/in-notes/rfc3986.txt Appendix C and help with long URLs that would otherwise wrap (and even if the link would initially work, it would often fail if forwarded as quoted.

[demiankatz]

Ere,

Thanks for this! A few notes:

1.) I split out your template change to a separate commit since it is not directly related to this refactoring.

2.) I significantly simplified your code here: bed4955 -- the "id" hidden filter is now "ids", and it's tab-delimited instead of using a pseudo-Solr syntax. I think this reduces the chance of edge case problems. Since MixedList is backend-agnostic, it seemed best to use a compact and easy-to-parse format for the hidden filter representation.

3.) I noticed that saved MixedList searches didn't display very nicely, so I added a custom display query here: df55b33

Please let me know if you have concerns/problems with my changes! Thanks again!