Hotfix/Colossalai layers (#92)

* optimized 1d layer apis; reorganized nn.layer modules; fixed tests

* fixed 2.5d runtime issue

* reworked split batch, now called in trainer.schedule.load_batch

Co-authored-by: BoxiangW <45734921+BoxiangW@users.noreply.github.com>

colossalai/nn/layer/__init__.py

@@ -1,3 +1,9 @@
 from .colossalai_layer import *
-from .fused_bias_gelu import bias_gelu_impl
+from .parallel_1d import *
+from .parallel_2d import *
+from .parallel_2p5d import *
+from .parallel_3d import *
+from .parallel_sequence import *
+from .utils import *
+from .vanilla import *
 from .wrapper import *