Fix titles

[ccstan99]

Strip newlines from titles. Also consider stripping non-alphanumeric chars from the title and "uncase" (all lowercase) when making hash_ids to catch more duplicates.

[Thomas-Lemoine]

so there are two ways where changes can be made:

• article.title
• article.generate_id_string()
  do you mean that strip new_lines modifies article.title, meaning the displayed article changes, whereas strip non-alphanum and uncase happen in article.generate_id_string(), meaning it won't affect how it's displayed later on?