Add SDL_WINDOW_RESIZABLE to the sdl window property
and call canvas->update() in the resize event.
Afterwards, if the canvas needs to be expanded by the window size by passing the size as an argument
to the update(canvas,elapsed) interface, it can be processed individually.
Fix some error:
* glViewport not controlled by framebuffer, and need to set manually when
target framebuffer is changed.
* change even-odd stencil operation, so no need to do third draw call to
clear stencil buffer
* fix the missing `GlCanvas::update` calls in Lottoe and LottieExtension
Selecting a tool without choosing the required tools
resulted in a usage error. Now, the activation
of the appropriate saver/loader for a given tool
is enforced.
examples are not considered a feature of ThorVG;
hence, they are excluded from the src directory.
This change allows developers to concentrate more effectively
on the core ThorVG sources for practical usages.
