Matrices revision

See merge request !45

Fixed AdEllpack up to 99x99 matrices. Larger matrices have increasingly different resulting vectors. FIXME.

Removed commented out code. Finalized cross-device assignment (Not ideal for CPU, but enough for benchmarking GPU).

Added basic functionality for cross-device copy assignment. Removed StripSize template typename as it was never used anywhere.

Fixed setCompressedRowLengths by getting around const vector. Fixed getStripLength and getGroupLength by using accessing methods instead of []. Fixed addElement to multiply the present value rather than the value that is being added.