Plugins want to use the existing mail infrastructure for sending custom
emails. If the plugin can register soy templates, the plugin can easily
extend one of the existing sender class (e.g. ReplyToChangeSender) to
send custom emails with these custom soy templates.
Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: Ic3adcbb73ed3f82395da4f273bc9fc856a50a257