Inspect results of parent subflows in edge conditions

[fridex]

Currently, one of the major limitations Selinon has is the fact that results of parent sub-flows cannot be used in conditions. It would be nice to include such capability.

[fridex]

This might be confusing in many cases since flows can have multiple tasks of a same type. A solution would be to include flags:

• any - similar to Python's any() - a condition is evaluated as true if any of parent tasks resutls (from parent subflow) meet given condition
• all - again, similar to Python's all() - a condition is evaluated as true if all parent tasks results (from parent subflow) meet given condition
• filter - this would propagate all parent tasks which results meet given condition, the ones that do not accept condition are omitted from parent in scheduled task
• every - this would schedule multiple tasks, each task would have exactly one parent task from parent subflow as if parent flow would be a parent task

Further inspection needed - e.g. what to do in more complex situations (possibly stick with all permutations as now with multiple parent of a same type).