Titlecase MSA alert types

Ticket:
https://trello.com/c/9zAer1Z4/491-lowercase-medical-device-alert-and-drug-alert
Merge pull request #320 from alphagov/titlecase-msa-alert-types

Titlecase MSA alert types
Stemming updates
Merge pull request #321 from alphagov/stemming-20141210

Stemming updates