* Added the underlying exception in the HttpManager to distinguish
    between errors in the client stack.
* Fixed ContainerResource check for duplicate key, the "new key"
    algorithm is now more random (ie it uses the whole scale instead of the
    object serial mask), as it was leading to infinite loops on huge sites.
*  Fixed deadlock in NegotiatedFrame. getVary() allowed a backward
    sync chain.
* Added a "equiv" method in MimeType to check for text/xml -
    application/xml rough equivalence on PUT
* Added Long support in HttpBuffer and HttpParser
* Fixed lock ordering in NewStoreEntry to avoid a deadlock
* Verification of connection availability on POST changed (need to
    have a fd_err + select to do it in a better way)
* Fixed deadlock when a file resource mark its parent as modified
    (backward locking, again)