Fix non-cuboid fields not updating. Fixes #590.

Non-cuboid fields should never have their DirtyFieldReason.DIMENSIONS
property set, this will cause the UPDATE query to fail.

The error message of the query wasn't displayed because SQL errors were
ignored by the DBCore.execute method. This commit also fixes that
problem.
Merge pull request #667 from rutgerkok/not-saving-to-database

Fix non-cuboid fields not updating. Fixes #590.