Fix gravizo pictures. One of them is not fixable.

[david-morales]

The encoder tool (http://www.gravizo.com/#converter) fails to convert the diagrams unless you enable the extra compatibility flag.

I have preserved the texts in a collapsible section, just for readability and edition purposes.

One diagram is not fixable. It seems that the definition itself is not complete.

Description

[] It needs and includes Unit Tests

Changes in Client or Server public APIs

[] It includes documentation for these changes in /doc.