Spacebar Menu: Small context fixes and cleanups

Bumped version to 1.8.4
Remove the Transform, Mirror and Snap to Cursor
from the Sculpt menu
Replace the separators with the switchable ones
in the VIEW3D_OT_Interactive_Mode_Grease_Pencil
Add a check for the Particle Edit in the
VIEW3D_MT_Object_Interactive_Mode

Small style cleanups, use toggle in Preferences