2 missed functions added to scst_user interface:

2 missed functions added to scst_user interface:

 - SCST_USER_UNREGISTER_DEVICE - to unregister device, flush mem reuse (SGV) cache and send UCMD_STATE_ON_CACHE_FREEING notifications for all freed buffers to the user space handler. Simple device close doesn't allow that, so all the cached buffers might look as "leaked" from the user space handler POV.

 - SCST_USER_FLUSH_CACHE - to flush mem reuse (SGV) cache and send UCMD_STATE_ON_CACHE_FREEING notifications for all freed buffers to the user space handler

+ some cosmetics

Docs update is coming

git-svn-id: https://scst.svn.sourceforge.net/svnroot/scst/trunk@665 d57e44dd-8a1f-0410-8b47-8ef2f437770f