share/examples - Fix cdev warnings
hammer - Fix max volumes check on mount time
hammer2 - major simplification 1/many (stabilization)

* Fix a dirty chain leak due to detached inodes and the delayed vnode
  deactivation that DragonFly does.  A cache_unlink() call was missing
  to properly cycle the vnode in the nrename path and a
  hammer2_cluster_delete() needed the DELETE_PERMANENT flag to handle the
  case where the vnode was already detached.

* Fix an inode reference count leak, callers of hammer2_inode_common_parent()
  were not properly dropping the returned inode.

* Fix a deadlock due to front-end vs write-thread interactions.  nvtruncbuf()
  calls must not be made with an inode lock held.

* Cleanup some debugging, add some debugging.
hammer2 - major simplification 1/many (stabilization)

* Remove the extra drop from hammer2_hardlink_consolidate().  It was dropping
  cdip in one path but not another.  The previous fix for the
  hammer2_inode_common_parent() use-cast flipped the problem around, but
  was otherwise correct (and more sane).
kernel/usb4bsd: Sync urtwn(4) with current FreeBSD.

This adds support for several (RTL8188EU based) adapters, among other
changes.

It should also fix the hangs we were seeing (using usb_pause_ls() now).

Thanks to Max Herrgaard <herrgaard@gmail.com> for testing it on a
RTL8188EU based adapter and to Christian Koch <cfkoch@sdf.lonestar.org>
for testing it with a RTL8188CU based one (Adafruit USB WiFi).