Simplicial

- Fixed coding style to conform (largely) to Python Black
- Separated main interface from representation

- Fixed broken setup.py

- Integrated barycentric decomposition contribution
- Added Python10 compatability and testing. Removed Python2.7 compatability
- Fixed issue with deleting 0-simplices corrupting the basis matrices
- Improved integrity checks in tests
- Refined exceptions raised

- Fixed package problem (simplicial.file not being included)

- Added a paper for the Journal of Open Source Software for the library
- Added various extra references to the bibliography
- Simplified some of the operations
- Improved copying to work with sub-classing
- Added filtrations
- Added generator functions for common structures, refactoring a little
out of the SimplicialComplex class
- Added numpy types on boundary matrices to reduce memory footprint

- Refactored internally to use boundary matrices
- Improved exception handling in a few places
- Changed TriangularLatticeEmbedding to embed any complex as
a lattice, relying on simplex order rather than names
- Python 2.7 and 3.7 compatibility, with tox tests
- Improved test coverage
- Moved to non-versioned requirements
- Added a tutorial to the documentation