Continual-inference

Added
- CoConv step impl in C++.

Fixed
- FLOPs module registration compatibility with ptflops >=v0.6.8.

Added
- Call-mode specific functions in `co.Lambda`

Added
- Support for functor in `co.Lambda`

Removed
- `nn.LayerNorm` from automatically convertible modules

Added
- `nn.LayerNorm` to automatically convertible modules

Added
- `ParallelDispatch` module.
- `Conditional` predicate print in `__repr__`.

Fixed
- Sequential `padding` computation.
- `Lambda` `__repr__` function prints.

Removed
- CI testing for python v3.6.