chore, add build status indicator to README.md

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
hygiene, avoid shadow decl in divrem() routine, div(3) is stdlib

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'code/hygiene' into next

* code/hygiene:
  hygiene, avoid shadow decl in divrem() routine, div(3) is stdlib