Salvaging what I can from the failed experiment, read more

I'm salvaging the changes to AccountManager and CharacterManager that
don't break the build too badly. This won't build, but it'll be easier to
rectify.

Also, I've reduced the length of the manager's method names, and renamed
sql_utility.*pp to sql_tools.*pp
Changed a bunch of method names, including Singleton<>
Merge branch 'develop', reviewed the managers' layout