Ensure that all member attributes are initialized

I ran the game through cppcheck and it spat out a bunch of member
attributes that weren't being initialized. So I initialized them.

In the previous version of this commit, I added constructors to
GraphicsResources, otherlevelclass, labclass, warpclass, and finalclass,
but flibit says this changes the code flow enough that it's risky to
merge before 2.4, so I got rid of those constructors, too.

desktop_version/src/KeyPoll.cpp

@@ -57,6 +57,8 @@ KeyPoll::KeyPoll()
 	linealreadyemptykludge = false;
 
 	pauseStart = 0;
+
+	isActive = true;
 }
 
 void KeyPoll::enabletextentry()