Remove calls to ScreenReaderDriver::IsActive() from other driver functions. Tolk_DetectScreenReader() takes care of this and the added security in doing it again when actually speaking is limited, but causes quite some performance overhead.
Minor code style fix.
Fix possible crash in ZoomText Speak function.
Don't finalize ZoomText driver on certain failures.
Add some whitespace to improve readability.
Inline ScreenReaderDriver base constructor, allowing to remove its source file.
Inline the IsRunning functions.