Review model files relationship diagram

[130s]

Since 3 formats are involved, it's not the simplest. So I made a diagram.

I also posted this into tutorial for creating a model for new end effector.

[k-okada]

@YoheiKakiuchi have that file, and he poseed somewhere but I could not find them
comment from @snozawa of jsk-ros-pkg/jsk_common#219 also related and valuable.

[130s]

Nice! @snozawa's diagram in this commentis helpful.

[YoheiKakiuchi]

This is another diagram including package name.

[snozawa]

I think it would be better to merge my diagram and @YoheiKakiuchi 's one.
In @YoheiKakiuchi , ros package names are explicitly written.
In my diagram, which parser programs are used is described.

I can send the file to @YoheiKakiuchi .