Infrastructure

We will use utility classes in libclient to provide a consistent lookup service to allow applications to find out the mime type and file extension for formatIDs. Create an ObjectFormatInfo class in Python that provides:
* a static singleton that can be called from anywhere in an application
* function to find the mime type based on a formt identifier string
* function to find the mime type based on an ObjectFormat instance
* function to find the extension based on a formt identifier string
* function to find the extension based on an ObjectFormat instance
* a default set of mapping data that ships with libclient as a CSV file
* the ability for calling applications to set a property (D1Client.resourcesDir) that determines where this CSV data file will live on disk
* the ObjectFormatInfo class should be able to reload itself at runtime, re-reading the CSV file so applications can refresh mappings without a restart