* Add utils to calculate model complexity info
* remove _InstanceNorm in unittest
* add docstring and increase unittest coverage
* fix deconv_flops_counter_hook to accept different data shape
* test when model is not a common instance
* put flops_counter.py and weight_init.py into mmcv/cnn/utils folder
* fix import name
* reformat some docstrings
* update the scripts with latest one and remove redundant codes
* directly represent a model without string and eval()
* reformat code
Jintao Lin