Add controller and view tests of sequence duplication

[#55911802]
Refactor duplication of lightweight activities

[#55911802]

Make it safer:
- accept new_owner as duplicate argument (consistent with sequence duplication)
- use transactions
- use bang version of save (due to transactions, rollback can be performed)
- it also ensures that sequence duplication will be handled correctly
  when duplication of activity fails
Fix cancan abilities related to sequences and activities

[#55911802]

Activities:
- class was passed instead of an instance
- is_locked isn't a valid property of a sequence
Fix duplication of invalid interactive page + add regression test

[#55911802]

Actually it's enough to ensure that interactive page has at lest one
interactive item to make sure that tests will fail without this fix.
Fix activity duplication test and related issue in model

[#55911802]

Test wasn't actually using invalid activity, but only activity that
had invalid page. When I set description to bad content, test
started to fail until #duplicate method was updated too.
Restyle "Create new activity" and "Create new sequence" buttons

[#70161558]
Remove CR character from styles.scss
Change how active_mailer is configured.

Also requires changes to config/mailer.yml (Not checked in) which looks
like this:

default: &default
  user_name: XXXX
  password: XXXX
  address: XXXX
  port: 25
  authentication: :login
  enable_starttls_auto: true
development:
  <<: *default
production:
  <<: *default
Use AWS::SES For Action mailer
Configure exception notifier to send mail to authoring-help@concord.org
Configure routes for testing mail sending and exception reporting.
Update view test related to "Create new activity" button

[#70161558]
Sequences: align the baseline of the title to the bottom of the logo

[#72112280]
Configure action_mailer to use SES in production.
Don't bother re-linking the mailer.yml file anymore. (use app_env … )
[#72428520] Replace snapshot wasn't replacing the snapshot!

https://www.pivotaltracker.com/story/show/72428520
Merge branch 'staging' into production

* staging:
  [#72428520] Replace snapshot wasn't replacing the snapshot!
  Don't bother re-linking the mailer.yml file anymore. (use app_env … )
  Configure action_mailer to use SES in production.
  Sequences: align the baseline of the title to the bottom of the logo
  Update view test related to "Create new activity" button
  Configure routes for testing mail sending and exception reporting.
  Configure exception notifier to send mail to authoring-help@concord.org
  Use AWS::SES For Action mailer
  Change how active_mailer is configured.
  Remove CR character from styles.scss
  Restyle "Create new activity" and "Create new sequence" buttons
  Fix activity duplication test and related issue in model
  Fix duplication of invalid interactive page + add regression test
  Fix cancan abilities related to sequences and activities
  Refactor duplication of lightweight activities
  Add controller and view tests of sequence duplication