Add dispose methods

[CodyJasonBennett]

Adds disposal methods, as described in #73. I've renamed geometry and program's remove method to dispose. Classes will only dispose of their internals, and user-defined parameters are left unmanaged for user-land control.

[CodyJasonBennett]

Should Mesh have its own disposal method where it will dispose of its program and geometry? My concern would be with shared programs/geometry and whether it's a good idea to let the user choose -- and thus open up to renderer or transform-level disposal.

[gordonnl]

Thanks again for your work!
This is a really good question - I share your concern for shared elements, however I suppose that's just something the developer has to control. Perhaps if there's a way to flag the geometries/programs to ignore disposal?

[CodyJasonBennett]

I think I'll only be eager to dispose of things internal to a class. Leaving the rest to the user can be annoying, but it only enables advanced usage.

[CodyJasonBennett]

Closing as stale. Noting #123 (comment), I'll try handling this in user-land with something like:

function dispose(gl: WebGL2RenderingContext, object: unknown): void {
    if (object === null || (typeof object !== 'object' && typeof object !== 'function')) return;

    switch (object.constructor) {
        case WebGLBuffer:
            gl.deleteBuffer(object);
            break;
        case WebGLFramebuffer:
            gl.deleteFramebuffer(object);
            break;
        case WebGLProgram:
            gl.deleteProgram(object);
            break;
        case WebGLQuery:
            gl.deleteQuery(object);
            break;
        case WebGLRenderbuffer:
            gl.deleteRenderbuffer(object);
            break;
        case WebGLSampler:
            gl.deleteSampler(object);
            break;
        case WebGLShader:
            gl.deleteShader(object);
            break;
        case WebGLSync:
            gl.deleteSync(object);
            break;
        case WebGLTexture:
            gl.deleteTexture(object);
            break;
        case WebGLTransformFeedback:
            gl.deleteTransformFeedback(object);
            break;
        case WebGLVertexArrayObject:
            gl.deleteVertexArray(object);
            break;
        default: {
            // Shallow dispose of known properties
            for (const key in object) dispose(gl, object[key]);
        }
    }
}