Fixed a couple of memory leak issues

• In SceneForGLK, we weren't hanging onto the drawnFramerateText and drawnViewFocusCoordsText strings properly (formerly lastFramerateText and lastViewFocusCoordsText).  Now they're retaining properties.
• In SceneViewControllerForCG/GLK#initCommon, the leak detector is just being a dick.
Fixed up draw/updates for SceneViewControllers

SceneViewControllerForGLK was lacking FPS measurement.  SceneViewControllerForCG's draws and updates were mismatched to SceneViewControllerForGLK's.  Both have been addressed here, along with other fixes and improvements.

SceneViewControllerForCG:
• now tracks the last two update and draw times (instead of just 1) and reports the difference between them for timeSinceLastDraw and timeSinceLastUpdate (matching GLKViewController behavior) rather than the literal time since the last draw/update.
	• Comment-doc notes about this have been added for the properties.
	• _lastDrawTime and _lastUpdateTime became _lastTwoDrawTimes and _lastTwoUpdateTimes.
• onDisplayLink: now more-closely matches GLKViewController functionality: update happens first, then draw, then the update and draw times are updated.
	• Comments added explaining all this.
• viewWillAppear auto-unpauses and viewWillDisappear auto-pauses like GLKViewController.
• Intermediate draw method added to parallel update.

SceneViewControllerForGLK:
• is now the GLKView's delegate, instead of the Scene.  SceneViewControllerForGLK now handles the glkView:drawInRect: callback and calls out to the Scene's drawForView:.
	» This is so that we can poke in and measure draw timing.
	» As a nice side-effect, this allowed the unification of Scene draw methods.
• updates _lastTwoDrawTimes and _lastTwoUpdateTimes in glkView:drawInRect: and update and stores the intervals for measured FPS calculation.
	• _lastTwoDrawTimes and _lastTwoUpdateTimes added in the same manner as SceneControllerForCG.
	• measuredTimeSinceLastUpdate and measuredTimeSinceLastDraw added as well, using the same logic as SceneViewControllerForCG's timeSinceLastUpdate and timeSinceLastDraw.
	• setPaused: hook that clears out our draw/update times (so as to not get super-large values).
• SceneForGLK ivar and guarded scene accessors replaced with a plain Scene and default accessors.  The draw call is no longer SceneForGLK-specific and the baseEffect set is probably going away.

So:
• Scene and SceneForCG and SceneForGLK derivatives use a unifies drawForView: now.
	• Some of the rects that were passed in are now calculated by view.bounds.  I suspect things are going this way all over.
• SceneForGLK no longer adheres to GLKViewDelegate.
• All usages of self.displayLink.timestamp replaced with CACurrentMediaTime().
	» I started implementing a mach_time grabber and then realized that CACurrentMediaTime() is exactly that.  So we're going to use that from now on.

Also:
• SceneViewControllerRecentIntervalInfo sample counts upped to 30 from 5 in both usages.
• SceneViewControllerRecentIntervalInfo changes to use NSUIntegers instead of ints.
	» I'm not sure why.  This seem more right.  Maybe I'll transition to this over time.
• SceneViewControllerRecentIntervalInfoMake() function added to simplify construction a bit.
• pauseOnWillResignActive and resumeOnDidBecomeActive turned off.  Both are to heavy; we really only want the current controller to be paused/resumed on these events, and we're already doing that.
• Removed an unnecessary ‘paused = NO’ for the initial controller.  (It gets unpaused during applicationDidBecomeActive: and viewWillAppear already.)
• SDTLog macros changed to not have a line break between the method/function location and the text.  It was just too hard to read.