Change default initializers and types as discussed on Skype 2/27

Change EGLattribs and EGLcontextAttribs to point to const EGLint, to match
the default attrib arrays
Remove initialization of eglDisplay, eglSurface, hWindow, hDisplay within class
declaration, where they cannot be initialized
Add default size parameters to Window, I don't think one constructor can
call another constructor within the same class