Correct coke's mesh position and add bottle's mesh

Update tutorial for mesh preparation
Merge pull request #4 from hris2003/master

Correct coke's mesh position and add bottle's mesh
Make example scripts visible
Merge pull request #5 from hris2003/master

Fix the visibility of example scripts
Revert "Fix the visibility of example scripts"
Merge pull request #6 from wg-perception/revert-5-master

Revert "Fix the visibility of example scripts"