feat: add res_multistep, res_2s sampler and bong tangent scheduler (#1234)

stable-diffusion.h

@@ -48,6 +48,8 @@ enum sample_method_t {
     LCM_SAMPLE_METHOD,
     DDIM_TRAILING_SAMPLE_METHOD,
     TCD_SAMPLE_METHOD,
+    RES_MULTISTEP_SAMPLE_METHOD,
+    RES_2S_SAMPLE_METHOD,
     SAMPLE_METHOD_COUNT
 };
 
@@ -62,6 +64,7 @@ enum scheduler_t {
     SMOOTHSTEP_SCHEDULER,
     KL_OPTIMAL_SCHEDULER,
     LCM_SCHEDULER,
+    BONG_TANGENT_SCHEDULER,
     SCHEDULER_COUNT
 };