Add Escrow support:

Escrow replaces the existing SusPay implementation with improved
code that also adds hashlock support to escrow payments, making
RCL ILP enabled.

The new functionality is under the `Escrow` amendment, which
supersedes and replaces the `SusPay` amendment.

This commit also deprecates the `CryptoConditions` amendment
which is replaced by the `CryptoConditionSuite` amendment which,
once enabled, will allow use of cryptoconditions others than
hashlocks.

src/ripple/protocol/TxFormats.h

@@ -35,10 +35,10 @@ enum TxType
     ttINVALID           = -1,
 
     ttPAYMENT           = 0,
-    ttSUSPAY_CREATE     = 1,
-    ttSUSPAY_FINISH     = 2,
+    ttESCROW_CREATE     = 1,
+    ttESCROW_FINISH     = 2,
     ttACCOUNT_SET       = 3,
-    ttSUSPAY_CANCEL     = 4,
+    ttESCROW_CANCEL     = 4,
     ttREGULAR_KEY_SET   = 5,
     ttNICKNAME_SET      = 6, // open
     ttOFFER_CREATE      = 7,