GL: Respect minimum UBO alignment requirement (#794)

* GL: Respect minimum UBO alignment requirement

* Use glBindBufferRange for UBOs

* Fix fragment shadergen UBO bindings

* Nit

include/renderer_gl/renderer_gl.hpp

@@ -101,6 +101,9 @@ class RendererGL final : public Renderer {
 	std::unique_ptr<StreamBuffer> hwVertexBuffer;
 	std::unique_ptr<StreamBuffer> hwIndexBuffer;
 
+	// Current offset for our hw shader uniform UBO
+	u32 hwShaderUniformUBOOffset = 0;
+
 	// Cache of fixed attribute values so that we don't do any duplicate updates
 	std::array<std::array<float, 4>, 16> fixedAttrValues;