added a wrapper around the templating engine, to be able to have default values
for some template variables.
{{! template for an annotation displayed in a segmentWidget }}
<div title='{{divTitle}}' id='{{id}}'
class='Ldt-iri-chapter'
style='left: {{startPourcent}}%;
width: {{endPourcent}}%;
background:#{{hexa_color}};'
>
</div>