[Converge] merge CHANGELOG.md with joyent/node ChangeLog

[rvagg]

We need 0.10 and 0.12 entries in the CHANGELOG.md here, they can be copied as-is with basic markdownification as was done in 5d8b232fc

[rvagg]

This 4.0.0 issue is open for takers if someone on @nodejs/collaborators is looking for something to do. We need to interleave the changelog entries according to date, no need to do anything more fancy than was done in 5d8b232fc.

[pmq20]

#2536