WIP: Depth morphing and pectoral rotation based gravity

Hey, a quick update on what will be included in TittyMagic 5.2 alpha 4.

Soft joint position based depth morphing

Demo video: https://mega.nz/file/gcdQ3Lpa#KrD2E6BTj4nIYKLlrYpDWCw7-vX3NWUrilAOql6fHgY 

I implemented a breast depth calculation based on the soft collider joint positions. The depth is calculated as the distance from the average of nipple and areola soft joint positions to the average of breast outer soft joint positions. 

This distance is responsible for half of the overall depth morphing, the other half is still based on the previous method (distance along the chest forward axis between the chest and the breast's linked pectoral joint). Combining the old and new methods allows gravity and other forces to affect morphs like before, but improves the accuracy of morphing from collision and makes it overall more dynamic and sensitive.

In the demo you can see the morphs starting to change a little as soon as there's a change in the calculated depth. With the old method that doesn't respond to soft physics, there would be an inch deep dead zone when pushing the breast in, and the morphs would change more abruptly.

Pectoral rotation based breast gravity

Demo video: https://mega.nz/file/scdABJBb#QtMhPLaIBUrbP-f5rpvMXVA58MKYqNV6Sjv3lWRX1AM 

Previously, breast gravity has been based on the chest angle (in world space), which has meant that physics settings like Up/Down Angle Target get the same value for both breasts. I realized that I can actually use the pectoral joint's rotation that each breast is physically linked to. This not only allows the breast gravity effect to be different for each breast but also makes it respond to the breast's movement due to collision and animation.

In this video the white line indicates the chest joint's Y axis, while the green line indicates each pectoral joint's Y axis. You can see the pectoral joint rotate a little when the breast is moved, while the chest angle stays static, and the rotation feeds back into the Up/Down Angle Target value. A similar effect applies to other parameters adjusted by breast gravity (Left/Right Angle Target, Spring, Damper and In/Out Spring).

There's a still bunch of things like physics default values to change and test, but I should be able to get the new alpha out in a few days. Stay tuned!

-everlaster