updated documentation

docs/sdk/overview.rst

@@ -143,9 +143,6 @@ implementing the ``Msg`` interface:
     	// Must be alphanumeric or empty.
     	Type() string
     
-    	// Get some property of the Msg.
-    	Get(key interface{}) (value interface{})
-    
     	// Get the canonical byte representation of the Msg.
     	GetSignBytes() []byte
     
@@ -175,9 +172,6 @@ Messages can specify basic self-consistency checks using the ``ValidateBasic()``
 method to enforce that message contents are well formed before any actual logic
 begins.
 
-Finally, messages can provide generic access to their contents via ``Get(key)``,
-but this is mostly for convenience and not type-safe.
-
 For instance, the ``Basecoin`` message types are defined in ``x/bank/tx.go``: 
 
 ::