Fix issue with clipped drop downs.
Move properties to drop down type.

Seems to make more sense.
Make sure drop down is shown.

Previously the name field drop down wasn't visible, even if it contained
values.
Fix issue with scroll bars and drop down.

The scroll bars of the scrollable pane overlaps the drop downs. To
alleviate this we'll make sure the bottom of the scrollable pane is
padded.
Limit to top properties only.
Don't use combobox if no suggestions.
Don't suggest already added attributes.
Reasses suggestions after creating property.
Added more prototypes.

These are matches against the core properties defined in cyphesis. As
more gameplay is defined we'll add more here. We might also perhaps
provide different prototypes for different rulesets (currently we're
focusing on Mason).
Also print help text in tooltip.
Added a help window for new properties.
Only restrict adapter if suitable.

I.e. for some nested attributes we shouldn't restrict the adapter. In
fact, most restrictions only apply to top level properties.
Added even more prototypes.