Alpha Release - v0.3,1

New linalgrs release - v0.3.1!

New features:

• Added functionality to get the identity matrix, inverse matrix (s/o to @mariano-f-r) and the lu decomposition of a matrix!
• Implemented a Matrix with the Rust standard library Debug and Display trait (another @mariano-f-r s/o) to effectively get matrix output and debug output!
• Implemented the PartialEq trait to easily compare matrices across each other and check if they are equal
• A matrix macro to easily create matrices!