Improvements to protocol serialization:

A few serialization changes coming from m-of-n development:

 o Improve readability of SField.cpp.
 o Better initialization of STObject.
 o Trimming of STObject public methods.
 o Add STObject::getFieldObject and STObject::setFieldObject.
 o Make STObject::isEquivalent more robust.
 o Improvements to whitespace, overrides, and virtuals.

src/ripple/protocol/impl/LedgerFormats.cpp

@@ -88,7 +88,7 @@ LedgerFormats::LedgerFormats ()
             ;
 
     add ("EnabledAmendments", ltAMENDMENTS)
-            << SOElement (sfAmendments, SOE_REQUIRED)
+            << SOElement (sfAmendments,          SOE_REQUIRED)
             ;
 
     add ("FeeSettings", ltFEE_SETTINGS)