added api to documentation
Merge branch 'master' of https://github.com/CognitionGuidedSurgery/msml

* 'master' of https://github.com/CognitionGuidedSurgery/msml:
  Added MeshInfoOperators to get basic information about surface meshes, namely number of elements, volume and surface area.
  Added displacement constraints to sofa exporter
Testing bug: NotImplementedError: Wrong number or type of arguments for overloaded function 'GenerateDVF'.
fix #42
Merge pull request #68 from CognitionGuidedSurgery/GenerateDVF_bug

fix output request data type in SOFAExporter
added colorama for terminal colors under windows
Add: Interface to use shell command as operators + conversion operator.
update: use sh interface in .xml
Add: Handling "output file was passed as input parameter"
Update hiflow_scene.tpl.xml
Update hiflow_scene.tpl.xml
Update hiflow3.py
Fix: Cache for "SOFAExporter modifies memory in render #67"
Merge branch 'master' of https://github.com/CognitionGuidedSurgery/msml
Fix: Operator xml interfaces: Moved inputs hidden in parameters to input section.
Fix: arguments were mixed up in ApplyMultipleDVF
Fix: arguments were mixed up in BarycentricTransform
Merge pull request #70 from CognitionGuidedSurgery/LegacyFormats

Legacy formats
IndexRegionOperator for triangles added
added xnat operators

Conflicts:

	src/msml/ext/xnat.py