UML of A60 included as *.tiff.
moved *tiff of uml
Merge branch 'issue23_uml' of https://github.com/iea-annex60/modelica-annex60
UML-graph included and referenced in information section.
Reverted MSL to 3.2.1.

This is for #24.
OpenModelica is using 3.2.1. Version 3.2.1 also fixes various uses of Modelica that are not according to the standard.
Updated UsersGuide.

This is for #21. The image was moved to the Fluid/UsersGuide directory (to reflect the class in which it is used). The description has been moved to the section 'Implementation' as most users, except for developers, may not need this information.
Included *.pdf and *.graphml and removed ¨*.tif
Merge pull request #24 from iea-annex60/issue23_uml

Merge Issue23 uml after including *.pdf and *.graphml