CheckedInByUser now behaves more like Author
Rename user -> userString
Add authorUser field and constructor overload.
This will allow users to be resolved earlier.
Add ability to set "checked in by" user.
Added TFSTeamProjectCollection field and initializing in constructor.
Convert TFS's Changeset and Change to our ChangeSet and Item, respectively.
getDetailedHistory() now uses the TFS API.