Fixed

• fix warnings
• fix add_assign with sparse tensors

Other

• Update symbolica to 1.1.0
• update linnet
• add readmes
• Release spenso-macros 0.3
• update to symbolica 1.0
• update sympolica to 0.20
• Properly precontract scalars
• Refactor coefficient conversions to support generic float types
• working pow and fun execution
• working pow execution with wrapping
• add function generic key