Select filtering mode should match to any part of the string, not just prefix

[Joonas Lehtinen]

This changes the working logic (to better direction). If there is no oblications, I would do this change

[Artur Signell]

In my opinion the behaviour should be selectable through the API. Sometimes you want the select only to match by prefix, sometimes on substring.

Another way of implementing this would be to add the possibility to specify additional properties that should be prefix-matched. E.g. if I have a list of items "Value / Description" and want the user to be able to search (prefix) on either value or description I could do select.addSearchProperty(DESCRIPTION) and it would check both value (displayed property) and DESCRIPTION property for a prefix match.

[Marc Englund]

OptionStream? filter now changeable