Free-text search in "Select Attributes" dialog

[rappen]

When adding attributes to a query by using the "Add" -> "Attributes..." dialog, in would be nice to be able to filter attributes in the list using a freetext field. For example, writing "cint_" in the text field would show only the attributes with schema-name or Friendly Name beginning with "cint_".

The search should be case-insensitive.

Usage of wild-cards ("*") would be nice.