Remove JSON Spirit wrapper, remove JSON Spirit leftovers

- implement find_value() function for UniValue
- replace all Array/Value/Object types with UniValues, remove JSON Spirit to UniValue wrapper
- remove JSON Spirit sources

src/univalue/univalue.cpp

@@ -213,3 +213,15 @@ const char *uvTypeName(UniValue::VType t)
     return NULL;
 }
 
+const UniValue& find_value( const UniValue& obj, const std::string& name)
+{
+    for (unsigned int i = 0; i < obj.keys.size(); i++)
+    {
+        if( obj.keys[i] == name )
+        {
+            return obj.values[i];
+        }
+    }
+
+    return NullUniValue;
+}

src/univalue/univalue.h

@@ -161,6 +161,7 @@ public:
         std::istringstream(getValStr()) >> ret;
         return ret;
     }
+    friend const UniValue& find_value( const UniValue& obj, const std::string& name);
 };
 
 //
@@ -248,5 +249,8 @@ extern enum jtokentype getJsonToken(std::string& tokenVal,
 extern const char *uvTypeName(UniValue::VType t);
 
 extern const UniValue NullUniValue;
+
+const UniValue& find_value( const UniValue& obj, const std::string& name);
+
 #endif // BITCOIN_UNIVALUE_UNIVALUE_H