VIDEO: Make getFrameAtTime() public
VIDEO: Separate external and internal tracks

Prevents subclasses from having access to any audio track added from another file
VIDEO: Use the main isSeekable() in seekToFrame()
VIDEO: Improve accuracy of getFrameTime() and getFrameAtTime()
VIDEO: Add support for seeking in AVI videos with an index

Rewinding will work in any AVI video
ZENGINE: Create console method for parsing ALL .scr files

Useful for putting a breakpoint at certain ResultActions/Controls to
test out different instances of them.
ZENGINE: Fix LeverControl 'mirrored' support
ZENGINE: Keep a Graphics::Surface of the current background instead of re-reading the file each time

This is both more efficient and is part of the process of converting the entire game to RBG 565
ZENGINE: Transpose is done in RenderManager::readImageToSurface(), so remove it from mutateImage
ZENGINE: Force comparison to be between signed ints and ensure CLIP happens on a signed int
ZENGINE: Convert cursors to RBG 565

This is part of a series of commits converting all game assets to RBG 565 from
RBG 555. The argument is that certain backends do not support RGB 555.
ZENGINE: Convert image rendering to RBG 565

This is part of a series of commits converting all game assets to RBG 565 from
RBG 555. The argument is that certain backends do not support RGB 555.
ZENGINE: Convert RLF animations to RBG 565

This is part of a series of commits converting all game assets to RBG 565 from
RBG 555. The argument is that certain backends do not support RGB 555.
ZENGINE: Remove unnecessary pixel format switching from video code

This is part of a series of commits converting all game assets to RBG 565 from
RBG 555. The argument is that certain backends do not support RGB 555. AVI
videos are already in RGB 565, so we just need to remove the code that switched
the pixelFormat during videos.
ZENGINE: Use Surface::getPixels() rather than getBasePtr(0, 0)

Prevents unnecessary algebra
ZENGINE: Remove unnecessary check if a pointer was non-NULL before deleting.

I found out that you can call delete/free/delete[] on NULL and the function's defined
behavior is to do nothing.
Merge branch 'zengine-wip' into zengine