[FIX](CCC Scene Context Animation CustomMarks) Major regression that prevented animation when some options were active (valuesVisible on BarCharts, for example) and that caused custom extension marks (added to the existing CCC marks) to fail, due to CCC scene not being set up. Custom marks (without Sign), which through its proto inherit Sign methods: Sign methods - which are bound to a Sign - now detect when the method is being called through a custom mark and return the already computed value for the bound Sign. Relies on the assumption that anchor-targets/protos, in general, are b uilt before the ones which anchor on them. No attempt is made to execute the inherited methods in the context of the receiving mark, because, in general, it fails.