Make max failure count per field configurable

[cduplichien]

The max failure count per field should be configurable, defaulting to unlimited.
E.g. if I have 4 validation rules targetting one field, I should be able to configure a threshhold at which additional validation rules do not execute. This can also be useful in terms of prerequisites. For instance if I have a validation rule that a field must be numeric, followed by a validation rule comparing it to another number, I would not wish for the comparison rule to execute if the numeric rule had failed.
This behavior should also be overridable at the rule level, giving users the option to indicate that the rule should always run regardless of current error count for the field.

[twicksell]

How about a boolean on the rule to end validation on failure? Seems more specific to the rule/field than it does a global setting I can assign a number to.

[cduplichien]

I like the semantics for that better, but I think we should still have the ability to set a global default.

[twicksell]

Probably right, I could definitely see not wanting an errors response with 40 things wrong about a single field, probably just a handful are sufficient.

[cduplichien]

Kicking out of milestone 0.7.3. This feature should probably wait for issue #18 and issue #19 to ensure that whatever solution is developed also works with those integration points.