Add release notes for v0.6.6.

Add release notes for v0.6.5

Bump version number for v0.6.4

Merge pull request #52 from chrysn-pull-requests/actually-close-socket

transports: Close socket when closing the transport

Ensure packaging environment has required packages.

0.6.1.

0.6.0.

0.5.3.

0.5.2.

Version prep for 0.5.1 for my botched check.