Update changelog

(cherry picked from commit 6339e9839768597e30c29172d35f065591c209ec)
Fix misspell in change log.

(cherry picked from commit ede4816bfbff770ac6fc90b283f7d3b4466f49be)
Release of 3.6.0.
Remove Release Candidate from ChangeLog
ChangeLog with .0 for 3.6 release.
Note 3.6 leak fixes in bug section.

(cherry picked from commit 7d3b47c3ed54f821cea47f4c8c8c90333d46fa47)
Spaces not tabs in 3.6 change list.

(cherry picked from commit e32566e4e261e501f12b0695c33d7f50864823de)
Merge remote-tracking branch 'upstream/3.6.x' into 3.6.x
Merge branch '3.6.x' of github.com:basvandervlies/core into 3.6.x