Abstract client sorting tests to allow for easier addition of further tests
not used
[mms] Fix client-side sorting of display addresses.
[mms] Use Collator class, if present, to sort string fields on the client side.
Add additional client sort tests
Hide these identity prefs by default, as they are for advanced users
Better default
[mms] Fix client-side sequence sorting, when that is the only sort criteria.
Need to bump version from previous changes
[mms] Fix client-side reverse sorting.
Test native PHP utf7-imap conversion code also if mbstring is present on system
auth-type requires a username, so these are invalid examples
Make sure parts exists
[mms] Fix setting default port for POP3 URLs.
expanded tests for url parsing
[mms] Fix encoding/decoding URL elements in IMAP/POP3 URLs.

Need rawurl[en|de]code(), since we need to follow strict RFC semantics
[mms] Ignore message-specific URL parameters if a search query appears in an IMAP URL.