Invert and transpose functions

Probably need some refactoring.
Initial files for new API

Creating a new API with possibilities for using functions on raw arrays,
as well as a nicer API for 'wrapped' matrices.
Add isEmpty and isSquare functions  for arrays
Add array tests for dimensions and copy
Some tests for creating a matrix
Improve internal lifting and add tests for matrix()
Add, subtract and multiply arrays
Add 'plus' function to matrixy API
Add function to create identity arrays
Add LU decomposition for arrays
Add some doc comments and minor refactoring

Remove some unnecessary 'return's and add types into function
descriptions.
Add triangular matrix stuff to new api
Add createBlank for new api
Add Ax=b solver for arrays API
Implement tests for isUpper/isLower for LU decompose
Get and set for matrixy API
createIdentity and createBlank for matrixy API
Extract functional utilities
Add copy for matrixy API
Add subtraction for matrixy API