Make daily emails respect unsubscribe status [MJ-473]

- Re-add opt_in_myjobs to account form
- Add new options to daily emails
- Create a new view decorator that prevents some unauthorized access
- Make saved search digests update the last_sent member of a user's saved searches
Replace user.id with user.email [MJ-473]
PEP8 fixes, improve comment [MJ-473]
Merge branch 'master' into saved-search-not-unsubscribing__MJ-473
Merge branch 'master' into saved-search-not-unsubscribing__MJ-473
Merge branch 'master' into saved-search-not-unsubscribing__MJ-473

Conflicts:
	myjobs/decorators.py
	myjobs/tests/views.py
	myjobs/urls.py
	mysearches/tests/views.py
	mysearches/urls.py
	mysearches/views.py
	templates/mysearches/email_base.html
	templates/mysearches/email_digest.html
	templates/mysearches/email_single.html
	templates/mysearches/email_table_include.html
	templates/mysearches/saved_search_edit.html
Fix email templates [MJ-473]
Merge branch 'master' into saved-search-not-unsubscribing__MJ-473

Conflicts:
	mysearches/models.py
Fix layout for saved search digest emails [MJ-473]
Merge branch 'master' into saved-search-reverse-error__MJ-518
Change context vars for search emails [MJ-473]
Merge branch 'saved-search-reverse-error__MJ-518' into saved-search-not-unsubscribing__MJ-473

Conflicts:
	mysearches/models.py
	tasks.py
	templates/mysearches/email_base.html
	templates/mysearches/email_initial.html
	templates/mysearches/email_single.html
	templates/mysearches/email_table_include.html
Merge branch 'master' into saved-search-not-unsubscribing__MJ-473
Improve tests, rework search unsubscription/deletion [MJ-473]
Add missing email to digest template [MJ-473]
Make individual saved search unsubscription links pass through sendgird redirect [MJ-473]
Merge pull request #319 from DirectEmployers/saved-search-not-unsubscribing__MJ-473

Saved search emails not unsubscribing [MJ-473]
merged