Revert "lib/flex_proportions.c: fix corruption of denominator in flexible proportions"

This reverts commit 101ffb9c992c7dbb2701b93ed348e4a41b56d4cf.
Revert "lib: Fix possible deadlock in flexible proportion code"

This reverts commit 7c2ce44bb077a530eec17b253827608ebaa7037a.
Revert "lib: Proportions with flexible period"

This reverts commit 8a9e45a88478c0cbdc141762db65b076539f2015.