Reinforced joints for Dummy 13

After printing dummy in 500% scale I had several problems:

 - Parts tend to crack during assembly

 - not enough force in joints to hold position

So, this is modified joints to fix this problems. 

This solution was carefully tested and approved to be effective: 

Result of test and experiments - failed joints

Model is in 500% scale.

Print in PETG, avoid using PLA for joints.

See full assembly of dummy in 500% scale