rutil: Data: import capacity of pre-allocated buffers

git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@10187 ddefafc4-47db-0310-ae44-fa13212b10f2
resip/stack: WebSocket: allocate extra space in buffers for null bytes.  Ensure Data ShareEnum is not changed to Take by doing resize manually

git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@10188 ddefafc4-47db-0310-ae44-fa13212b10f2