Kannav Mehta

Results 3 issues of Kannav Mehta

As mentioned in issue #112. This PR adds two earlier excluded `clang-tidy` checks: - `google-readability-braces-around-statements` - `readability-braces-around-statements` The tests were not refactored because of incoming major changes proposed in #122....

Pull request for work done during GSoC21, Implementation of subtensor as tensors with subtensor_engine. Behave like tensors in expressions and obey all operators. Future Work - [ ] Subtensor iterator...

At line [130](https://github.com/hatcat/linear_algebra/blob/master/matrix_storage.h#L130), I believe this must be size.second.