Coding standard
Show chat alerts in icon tray only if not already seen
fix SVOs to render again
Look for and store the "Skeleton" type flag so that we can offer only skeleton
joints in the dropdown.
Add jointEyeLeft/jointEyeRight/jointNeck to list of nodes we check for on
upload.
Read the unit scale factor and include it in the offset scale.
Merge branch 'master' of https://github.com/highfidelity/hifi
Merge pull request #3613 from ctrlaltdavid/20112

CR for Job #20112 - chat alerts persist
Merge pull request #3616 from ZappoMan/fixSVOs

fix SVOs to render again
Merge pull request #3621 from ey6es/metavoxels

Sculpt brush, very rough conversion of heightfield patches to dual contour surfaces on edit.
Merge pull request #3623 from ey6es/master

For FBX files with marked "skeleton" joints, only show those marked nodes in the upload dialog.  Also added some more default node names to look for on upload.
Fix for Xcode warning.