* Updated filestore.FileStore implementation to use simple locking scheme. Refactored to make interface use pointers. Removed locks from tusd.Handler
* Refactored sample code to use pointer implementation of FileStore.
* Moved ErrFileLocked variable to datastore.go
* expose tusd.DataStore and extracted FileStore
* use pat for routing
* allow absolute BasePaths
* requires StripPrefix
* add support for 1.0 core
* update date in license