Pydec

* Add non linear decompose algorithm.
* Add nn modules (Linear, Containers, ReLU).
* Add `conv2d()`, `relu()`, `leaky_relu()`, `tanh()`, `sigmoid()` and `max_pool2d()`.
* Add new feature: autotracing.
* Add fast algorithm for `legacy_relu()`.
* Add `abs()`, `__rmatmul__()`, `mv()`, `mm()` function.
* Add `apply_()` and `map_()`.
* Add `c_apply()` and `c_map()`.
* Add `c_stack()`.
* Add argument `sum_residual` for `c_cat()`.
* Add `zeros()` and support for torch versions < 1.11.
* Add customized api registration.
* Update docs.
* Fix bugs.
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* Update doc notes and api documentation.
* Improve doc site style.
* Add decorator feature to bias decomposition context managers.
* Simplify bias decomposition algorithm names.
* Make `Composition.mul()` support `out` argument.
* Add `Composition.div()` and `Composition.div_`().
* Add `is_error_checking_enabled()`.
* Add alias `concat()` and `concatenate()`.
* Add alias `subtract()` and `multiply()`.
* Add `count_residual` argument for `c_numel()`.
* Add `div()` and `divide()`.
* Fix bugs.