refactor to use bindValue() instead of bindParam()

bindParam assigns by reference which has been confusing a few people
and tools, bindValue assigns it by value, slightly more intuitive
Merge branch 'master' of github.com:enwikipedia-acc/waca
optimise number of queries
rm more dead code
refactor authutils to be static analysis friendly.
rename class

(and remove require for it, autoloader should catch it. hopefully.)
pdo for loading of email sig
update inactive users
remove for now, broken with oauth
update to new table names
pdo for the last active stuff
more pdo for stats
fix query