added the feature importing rigid bodies and joints from pmx files.
fixed incorrect limits of rigid body constraints.
added margin frames property to vmd importer for rigid body dynamics.
added the feature for configuring scene settings easily.
changed default margin time for vmd animation.
fixed a bug caused by empty object scale.
fixed coordinate conversion.
changed the method of tracking rigid bodies.
removed unnecessary comments.
fixed limits of joints.
set 0 as IK influence values of dynamics bones.
added the properties for rigids and joints.
added a parameter for hiding rigids and joints.
added a property for importing only non dynamics rigid bodies.
updated README.
fixed the scale bug reported by iRi-E.
fixed the bug that two rigid bodies connected can not collide.
fixed dependency cycles.
Update README.md