Delete " _current" variable in App class.

App class does not need the object center position as a local variable.
Add the temp light and material settings.
Add the function that draws the path of moving object.
Change the method that calculate the object position.

- Add the velocity and friction vector.
Add the temp farclip value.
Merge branch 'develop' of github.com:tkt182/objectTracker into develop
Change the function that calculates the velocity of polygonShape.
Merge branch 'develop' of github.com:tkt182/objectTracker into develop
Add the .gitignore file.
Change the function that define camera move vector.
Change the function that calculate the next object position.
Change the key code below.

- close the camera to object.
- away the camera from object.
Change the method that defines the move direction.
Merge branch 'develop' of github.com:tkt182/objectTracker into develop
Add the "PolygonShapeSound" class that inherits from PolygonShape.

PolygonShapeSound class uses the soundstream.
Merge branch 'develop' of github.com:tkt182/objectTracker into develop
Add the function that reset position of polygonshape object.
Merge branch 'develop' of github.com:tkt182/objectTracker into develop
Change the vector parameter about moving object.
Add the function that makes camera position stable.