Issue #1234 - standardize some string conversions

src/plugin/AdblockPlusClient.cpp

 #include "PluginStdAfx.h"
 #include "PluginSettings.h"
 #include "PluginSystem.h"
 #include "PluginFilter.h"
 #include "PluginClientFactory.h"
 #include "PluginMutex.h"
 #include "PluginClass.h"
 
 #include "AdblockPlusClient.h"
 
@@ skipping 421 matching lines @@
 
 void CAdblockPlusClient::SetPref(const std::wstring& name, bool value)
 {
   Communication::OutputBuffer request;
   request << Communication::PROC_SET_PREF << ToUtf8String(name) << value;
   CallEngine(request);
 }
 
 std::wstring CAdblockPlusClient::GetPref(const std::wstring& name, const wchar_t* defaultValue)
 {
-  return GetPref(name, std::wstring(defaultValue));
+  return GetPref(name, defaultValue);
 }
 std::wstring CAdblockPlusClient::GetPref(const std::wstring& name, const std::wstring& defaultValue)
 {
   DEBUG_GENERAL((L"GetPref: " + name + L" start").c_str());
   Communication::OutputBuffer request;
   request << Communication::PROC_GET_PREF << ToUtf8String(name);
 
   Communication::InputBuffer response;
   if (!CallEngine(request, response)) 
     return defaultValue;
@@ skipping 97 matching lines @@
   Communication::OutputBuffer request;
   request << Communication::PROC_GET_HOST << ToUtf8String(url);
 
   Communication::InputBuffer response;
   if (!CallEngine(request, response)) 
     return L"";
   std::string host;
   response >> host;
   return ToUtf16String(host);
 }