MAINT: tools: add a script that produces a list of closed github tickets for a miletone
MAINT: tools: update author list tool
DOC: release: update autogenerated lists in 0.14.0 release notes
DOC: fix some minor issues in 0.14.0 release notes.
Merge branch 'pr/3415' into master.

Review at https://github.com/scipy/scipy/pull/3415
REL: set version to 0.15.0-dev, add 0.15.0 release notes.