Body may include the following variables which will be substituted in the email with a value
specific to each proposal:
{% templatetag openvariable %} proposal.title {% templatetag closevariable %}
e.g. {{ proposals.0.title }}
{% templatetag openvariable %} proposal.kind {% templatetag closevariable %}
e.g. {{ proposals.0.kind }}
{% templatetag openvariable %} proposal.main_speaker {% templatetag closevariable %}
e.g. {{ proposals.0.speaker }}
{% templatetag openvariable %} proposal.speakers {% templatetag closevariable %}
e.g. {{ proposals.0.speakers|join:", " }}
{% templatetag openvariable %} proposal.additional_speakers {% templatetag closevariable %}
e.g. {{ proposals.0.additional_speakers }}