add Invites collection
add Invites publication
add inviteUserByEmail method to invite users by email
add invites component
integrate invites rendering through a partial

had to specify an id for account form to make sure form submission handle does not mess with invitation form submission
introduce account controller

since account editing page now needs access to invites subscription
merge inviteUser and inviteUserByEmail into one method
update inviteUser call to work with the new method
propagate invitation call results through throwError
set invitation information for newly signed up users based on existing invites
do not allow multiple invites for the same person
clean seen errors before reporting invitation status
working on digest package
working on HTML emails
working on html email template
add handlebars-server package
add invitation email template
add a helper for signup url
email an invite to the new user
update message upon successful invite