Override operators for all struct types

[ulises-jeremias]

We have different types defined as structs in vsl, such as Matrix at vsl.la, among others. Would be good to override missing operators +, -, *, /, %, . . .

[ulises-jeremias]

@hungrybluedev I'll assign this to you

[hungrybluedev]

The first target for this is Matrix. Here's the plan I want to follow:

• [ ] Add unit tests for all functions of vsl.la written in V.
  • matrix.v - https://github.com/vlang/vsl/pull/35
  • matrix_ops.v - https://github.com/vlang/vsl/pull/38
  • ...
• [ ] Add operator overload methods based on blas functions.
• [ ] Add unit tests for newly added functions

[VinWare]

Added #67 to add unit tests for la/vector.v

[ulises-jeremias]

@VinWare thanks for your contribution!! I just merged your PR