Revert "temporary edge traversal should fail until visibleTo is set"

This reverts commit 0a66961e2c49abec20be36945b4e4832702426bf.
Revert "make split edges visible only to the context that created them. addresses #1025."

This reverts commit 964853d752bb3253f5fd86a8c43f6f2bc70a639f.