Update CHANGELOG.md

Update CHANGELOG.md

Update version to 0.8.1

Merge pull request #222 from learningequality/rtibbles-patch-1

Update CHANGELOG.md for 0.8.0

Bump version and update changelog

Merge pull request #205 from bjester/a-sync-story

Don't close sync session unless also older than cutoff

Merge pull request #203 from rtibbles/no_deleted_model_tracking_in_de…

…serialization

No deleted model tracking in deserialization

Merge pull request #194 from bjester/optional-ignore-on-resume

Add optional setting to ignore an existing process on resuming a sync

Merge pull request #177 from rtibbles/pycrypto_upgrade

Update supported Python versions and cryptography version

Merge pull request #175 from bjester/instance-id-fields

Rename instance json fields and add ID fields for convenient querying