Updated error handling in MapModelIndex

Report all errors in the logs as they happen, and make sure only
specific exceptions are caught.

This update is separated from the other cleanup tasks, as there is a
slight chance this could result in unexpected side-effects (the
trimFragment call should never result in a NumberFormatException; but it
is not realistic to ignore all possible exceptions because some random
exception thrown in the background) - this separation should make it
easier to revert the change if there are some issues.

Change-Id: Ie4e19e545624718ea865b855f3290a39f11c12a9
Signed-off-by: Balazs Varnai <balazs_varnai@mentor.com>
Signed-off-by: Zoltan Ujhelyi <zoltan.ujhelyi@incquerylabs.com>