Make datetimes timezone aware before serialising them. Fixes #10
Fixed typo
Store datetimes internally as UTC
Make sure datetimes stored as UTC are converted back to localtime
don't need to check value for None, since we know it's a datetime
remove redundant 'albums' entry in dict
convert aware datetimes to UTC on serialisation, not just naive ones
Convert naive datestamps to local time when deserialising
Add changelog entry for #11
Merge branch 'kaedroho-issue-10'