No longer re-fetching written files

It appears that valid eTags are now being returned with the WriteFile
response.  Removing the existing workaround to remove unnecessary
chattiness.
Added eTag valdiity test.
Added support for download delays

If an HTTP 202 is received following a download request, the (Sync) Read
method will now sleep for the appropriate amount of time and retry the
request.  This is not yet implemented for Async operations.
Added async download delay support.

Tweaked the HTTP 202 handling to better work with async methods.
Bumping version to 1.2