Don't update last_ip and last_login on *every* pageview

Instead, only do it every 5 minutes, *or* if the IP address
has changed. last_login is not used for anything important--
it's only displayed on the users' profile page.
Fix spoilers not being clickable in quotes

Also made blockquotes blockquotes. Instead of divs.
Increase thread subject, PM subject, and forum title sizes

Thread subject was annoyingly small. It has been increased 50%.
Similary, PM subjects have been increased to the same number.
Forum title has been increased to 36, because that's what it says.

Updated maxlengths as required
Merge pull request #86 from EvanFBC/fixes

Don't update last_ip and last_login on *every* pageview