Improved documentation.

This closes #264.
This commit also adds extends Modelica.Icons.Function to render the
icon properly.
Merged Annex60 library.
Merged Annex60
Merged Annex 60
Updated medium model for #265
Fixed documentation error for #267.
Merge branch 'master' into Annex60Sync
Updated reference results
Merge pull request #265 from lbl-srg/Annex60Sync

Annex60 sync
Updated release notes.
Changed parameters of solids from public to protected.
Reverted last commit

This was required as protected variables were accessed in the room model.
Merged Annex60 library.
Accepted new reference results
Removed duplicate parameter declaration.

Removed parameter m1_flow_nominal, as this parameter is already
declared in the base class.
Fix for DryCoilDiscretized in OpenModelica.

Reformulated the multiple iterators in the sum function
as this language construct is not supported in OpenModelica.
Added missing each attribute.
Reformulated model.

This avoids warnings from the OpenModelica parser.
Merged Valves from Annex60

This is for OpenModelica compatibility.
Added missing redeclare

This avoids an error in OpenModelica. This commit also improves the documentation.