Blender Git Loki

Fix mask extract and slice not preserving mesh symmetry options

When extracting new objects from a mesh in sculpt mode, it makes sense to keep
the current symmetry options and settings in the new mesh. In previous versions symmetry
options were stored in the tool settings, so this bug was not that obvious.

This also preserves the remember settings in the new object, which is also the desired
behaviour.

Reviewed By: sergey, mont29

Differential Revision: https://developer.blender.org/D9417