make properties optional

[FND]

sometimes - particularly when looking at the relational diagram - you're not interested in the individual properties, so it'd be nice if those could be hidden

for now I hacked this line to remove those properties (retaining foreign keys though) - but not sure how best to introduce an option that is passed through to the respective method

[postmodern]

Ah good idea. The first idea that sprung to mind was to add :properties and :foreign_keys Boolean options.