Create rudimentary matrix dtype
Add support for bulk float replies
Add matrix dependency to redis
Add matrix Redis datatype

* Adds XGET and XSET commands
* XSET rplies with dimensions and shape of matrix
* XGET replies with content of selected subregion of matrix

Shape reply:
* Number of dimensions (dims)
* dims replies for the size of each dimension (shape)

Content reply:
* Number of dimensions (dims)
* dims replies for the size of each dimension (shape)
* product(shape) doubles for each value
Slice and set values in subregion
Remove unused function
Add XZEROS and XONES for creating matrices
Add XEYE command for creating identity matrices
Add rdb persistence for matrix type