use separate icons for block and inline elements

Use separate icons for block and inline elements and invert the logic of
the inline element filter. Use the new inline element icon also for the
toolbar button of the inline element filter.

The text content now ends with an elipsis if it is trimmed.

https://bugs.eclipse.org/bugs/show_bug.cgi?id=407821

Change-Id: I68e82a99c173d5c322803595a28dd68837e35abd
11 files changed