Parse errors during file open fail silently

[cbielow]

When opening a file, which cannot be parsed (due to parse errors), see e.g. #28, Protege will simply not show anything in the user interface. It behaves as if the user did not try to open a file.
In reality, the log window shows a bunch of errors, but the user has to know that this log window exists, and open it manually to see what the problem was.
The UI should at least show a messagebox or (better) open the log window automatically if an error was encountered.

Tested with Protege 5.5.

Minimal example (save as bug.obo)

import: http://purl.obolibrary.org/obo/pato.obo

[Typedef]
id: has_regexp
name: has regexp

silently fails (until #28 is fixed at least) and does nothing in the UI.