set valency for all atoms when reading MDL v2000
Revert "[bug:1198] valency information is now always written"

This reverts commit 1f60f66b0889415954493f9763c93f2495a12441.
Revert "removed ignored setting from unit test"

This reverts commit 5c614f590961d4704a872a174ceac7533272d2f9.