Fixes #443.
Extract output buffering to function.
Use regular buffering if gzip option not set.
Use buffering in AJAX requests, to avoid “headers already sent” warning
in some situations.

No longer supporting PHP 5.1.
Fixes #394

And now we have local Joomla integration, we don't have to fail if the Joomla plugin isn't installed.

Also define QA_PASSWORD_HASH for password strategy.

10x faster with many blocked IPs

Store phrases in one variable, return as soon as possible. This results in extra includes in some circumstances but overall it's still faster.

From PRs by @pupi1985 (unmergeable due to file structure changes).
Closes #69.
Closes #126.