FreeSWITCH-FS-7269

Sigificant changes to the core state machine :)
Visually status of channels will only be DOWN once all resets/blocks are cleared.
Therefore if any reset/block is active on a channel, the channel state will be in RESTART not DOWN.

Logic Change

SUSPENDED
   -> Originally used as intermediate state. Purpose is to handle a condition
      from any state and go back to the previous state.
      Conditions: such as  block/ucic.
   -> Updated logic is that SUSPEND will be smart enough not to
      go back to just any state.  SUSPEND will only go back to
      UP - if call is still up
      RESTART - if for any reason singaling is not up due to
                blocks/resets/etc...
      DOWN - if signaling is UP - no resets/blocks
      In this case we avoid infinite loops due to state jumping
      from STATE->SUSPEND->STATE->SUSPEND
HANGUP_COMPLETE
   -> If call is in use and a RESET comes on a call
      the RESTART state will first try the HANGUP_COMPLETE state.
      HANGUP_COMPLETE will Tx RSC and wait for it.
      Reset Response handle was updated if current state HANGUP/HANGUP_COMPLETE
      go back to RESTART state.  Which will call HANGUP COMPLETE due to
      channel in usage and HANDLE_COMPLETE will clear RESET condition and go back to DOWN
TERMINATING
   -> This state is used to hangup a call. Sends a signal to FS.
   -> Usually TERMINATING state stays in TERMINATING until FS comes back.
   -> I added a condition in case of RESET on the line though TERMINATING
      will go back to RESTART.
      This allows us to process RESET commands even though we are
      in the middle of hanging up.
Block Handler
   If BLO is received on circuit is already blocked,
   we failed to trasmit BLA.  We should always ack the BLO
   even though it was alrady in blocked state.

Fixed & Tested

S UP --> place call --> relay down --> hangup --> relay up-->
   Confirm that call is hungup properly.
   In this condition, on relay up the circuit  is put into RESET.
   Since circuit is still in use, it will HANGUP first, then RESET
   then clear pending BLOCK.

S UP --> place call -> Tx RSC on call.
   Used to cause infitie loop
   Confirm call is cleard properly

Re-Tested

S UP --> place call -> Rx RSC on call
   Confirm call is cleard properly

S UP --> place call -> Rx BLO -> hangup -> place call
   Confirm call cannot be placed
   Tx UBL
   Confirm call can be placed

S UP --> place call -> Rx BLO -> Tx BLO -> hangup -> place call
   Confirm call cannot be placed
   Tx UBL
   Confirm call cannot be placed
   Rx UBL
   Confirm call can be placed

S UP --> place call -> relay down --> Rx BLO on channel from telco
     --> relay up
   Confirm that relay detects the BLO channels even though relay was down

Tx AIS -> S Start -> Confirm HW block -> Tx AIS off
   -> Confirm hw block clear and UP

S UP -> Tx AIS -> Confirm HW block -> Tx AIS off
   -> confirm hw block clear and UP

S UP -> relay down -> Tx AIS -> relay up -> Tx AIS off
   -> confirm all back up
   -> In this condition BLO will not go out due to PAUSE

S UP -> Tx AIS -> relay down -> Tx AIS off -> relay up
   -> confirm all back up
   -> In this condition UBL will not go out due to PAUSE