Updates to gist:requires. Fixes #183.

[rjyounes]

• Remove domain and range constraints
• Change definition, add an example

[rjyounes]

@dylan-sa Let me know if you can think of a better definition. I'm not thrilled with this one.

[dylan-sa]

@rjyounes Looks good to me. I think the definition is tough to improve, but I'll offer a couple alternatives in case they inspire some tweaks:

• 'The occurrence or existence of the object is a necessary condition for the occurrence or existence of the subject'

• 'The object's obtaining is a necessary condition for the subject's obtaining'

These options are a little more wordy, but they may help to paint a picture of what's really going on when we say 'x requires y'. For example, 'the contract requires two signatures' might mean 'the existence of two signatures is a necessary condition for the existence of the contract'.

[rjyounes]

DECISION: One predicate, define as

"To need something or to make something necessary."

scopeNote to indicate the different senses.