* Split struct niobuf into niobuf_local and niobuf_remote

* Split struct niobuf into niobuf_local and niobuf_remote
  - niobuf_remote is offset, length, xid, and flags
  - niobuf_local is all of the above, plus an address and sometimes a page
  - The former is sent across the network, the latter used internally

* Small ldlm fixes brought over from the (now-defunct) ldlm_testing branch
  - SMP deadlock fix
  - comment fix

* Bulk descriptor refactoring
  - You create a bulk descriptor and then n bulk pages that get hooked in
  - Pages sent all at once, optional callback per page
  - Another optional callback when the final ack has been received, although
    Eric tells me that elan doesn't guarantee packet ordering, so this needs
    revisited

* A few key bugfixes in the MDC/MDS/OSC/OST bulk code; these probably bit us if
  we sent it a signal during bulk processing

* A few LOV pieces (mostly in genops.c)
  - A temporary gen_multi_setup/cleanup to get the LOV rolling; it won't remain
    in this form

I've tested these fixes, but not exhaustively.