CLN: cleanup arguments in generate_code.py
PERF: Limit memmove to >= 256 bytes, relax contiguity requirements

 (only the stride in the dimension of the copy matters)
Merge branch 'stephenwlin-memmove-limit'

* stephenwlin-memmove-limit:
  PERF: Limit memmove to >= 256 bytes, relax contiguity requirements
  CLN: cleanup arguments in generate_code.py
DOC: update RELEASE.rst
BUG: GH2903, implemented xs for axis=1 with a level specified