Improved API, Speed, bugfix a big release

• SOLT is now PyTorch Native
• All the transform subtract the mean and std by default
• Implemented a proper serialization and deserialization
• Allowed to use dict instead of a data container
• Introduced shorter transform names
• Implemented a fair benchmark to compare with other libraries
• Fixed a bug of JPEGCompression (@tiulpin )
• Added IntensityRemappping transform (@soupault )

This release is not backward comparible