Misc edits
Fix error on implementation loading
Fix vector-dot
normalise tests using equals with epsilon
Refactor ns
Add pm stub
Move e* to main core.matrix API
Misc edits
Add subvector protocol
renames
subvector of NDWrapper
default implementation for subvector and tests
subvector compliance tests and fixes
persistent vector subvector
keyword coerce
improved examples
add cross-product protocol
Add cross product default implementation
Cross product tests
Mutable add! and sub! implementations