Keyboard Work Started

I started changing the keyb3 implementation to use SDL2 Scancodes and
Keycodes. Still needs quite a bit of work, though.
First commit

Added a mostly blank README-SDL2 file.
SDL_Window Hack

Because of how SDL2 handles its windows and rendering and the hack used in getting the Shadowgrounds to run properly (IStorm3D.h
header file), I added an SDL_Window variable to IStorm3d.h.
Storm3D.cpp SDL2 update

Did a full update on Storm3D to use SDL2. There are probably bugs in
this code, but I plan on working them out as I go.
keyb3.h SDL2 Update:

Updated keyb3.h with new SDL2 code.

Because keyb3 was using unicode originally and SDL2 uses scancodes, this could probably be completely rewritten.
orvgui2.cpp key3b Update

Updated the orvgui2.cpp class to use the updated key3b class.
keyb.cpp SDL2 update

Updated the keyb.cpp to comply with SDL2.
SDL2_Threading update

Had to update the c2_thread class since SDL2 uses a differerent setup
than in SDL1.2. What was added was a thread name to allow for
diferentiating between threads.
SDL2_Threading update 2

Forgot to update the header file to use the new naming convention.
GL_SwapBuffers Storm3D_Scene.cpp Fix

In SDL2, SDL_GL_SwapBuffers was changed to SDL_GL_SwapWindow and takes
an SDL_Window input
Keyb3 temporary video_player fix

Because of how I had to update the input handling to work with SDL2
(which has issues in itself), to get the storm3d_video_player class to
compile, I had to add an SDL_Window input to it that would get passed to
the Keyb3_UpdateDevices method.
Texture GL_SwapBuffers fix

Updated Storm3d_Texture.cpp SDL_GL_SwapBuffers to comply with SDL2.
SDL_GetKeyState BuildingMap fix

GetKeyState was changed to GetKeyboadState in SDL2.
Keyb3 GameController fix

Updated GameController.cpp to use the Keyb3 fix from a previous commit.
GameController header fix

I forgot to update the header file, too.
OptionsMenu Keyb3 fix

Updated the OptionsMenu class to use the update GameController class.
Shadowgrounds Main Class Full Update

Updated Shadowgrounds.cpp to comply with all previous updates and
fixes. It should compile now.
Updated README-SDL2:

Now it's more useful and has basic compile instructions for how to
compile the SDL2 version.
SDL_Window Double Window Fix Start

I figured out why there were two windows being drawn in Windowed Mode -
the if statements in the SetWindowedMode and SetFullscreenMode methods
of the Storm3D class need some work.
Window Work

Added a CheckWindowCreated function to comply with SDL2 standards.
Cleaned up the SetWindowedMode function by removing most of the old code
from it.
Added appropriate comments to the new functions to comply with the rest
of the code.