Include Steinberg PR responses (surge-synthesizer#573)

We sent 3 pull requests to steinberg for vstgui and they correctly
responded that 2/3 were indicative of us not using their API correctly

As such I've removed those commits from vstgui/surge, applied the
changes to our code, and have confirmed that the two issues
(capture on mouse click and diacriticals and emojis in patch
and category names) work with the vstgui without the associated
incorrect patches.

The final patch for checmark submenus is still in vstgui.surge in
this commit

Closes surge-synthesizer#571

src/common/SurgeStorage.cpp

@@ -341,8 +341,26 @@ void SurgeStorage::refreshPatchlistAddDir(bool userDir, string subdir)
    for (auto &p : alldirs )
    {
       PatchCategory c;
+#if WINDOWS
+      /*
+      ** Windows filesystem names are properly wstrings which, if we want them to 
+      ** display properly in vstgui, need to be converted to UTF8 using the 
+      ** windows widechar API. Linux and Mac do not require this.
+      */
+      std::wstring str = p.wstring().substr(patchpathSubstrLength);
+      std::string ret;
+      int len = WideCharToMultiByte(CP_UTF8, 0, str.c_str(), str.length(), NULL, 0, NULL, NULL);
+      if (len > 0)
+      {
+          ret.resize(len);
+          WideCharToMultiByte(CP_UTF8, 0, str.c_str(), str.length(), &ret[0], len, NULL, NULL);
+      }
+
+      c.name = ret;
+#else
       c.name = p.generic_string().substr(patchpathSubstrLength);
       c.numberOfPatchesInCatgory = 0;
+#endif
 
       for (auto& f : fs::directory_iterator(p))
       {
@@ -351,8 +369,21 @@ void SurgeStorage::refreshPatchlistAddDir(bool userDir, string subdir)
               Patch e;
               e.category = category;
               e.path = f.path();
+#if WINDOWS
+              std::wstring str = f.path().filename().wstring();
+              str = str.substr(0, str.size()-4);
+              std::string ret;
+              int len = WideCharToMultiByte(CP_UTF8, 0, str.c_str(), str.length(), NULL, 0, NULL, NULL);
+              if (len > 0)
+              {
+                  ret.resize(len);
+                  WideCharToMultiByte(CP_UTF8, 0, str.c_str(), str.length(), &ret[0], len, NULL, NULL);
+              }
+              e.name = ret;
+#else
               e.name = f.path().filename().generic_string();
               e.name = e.name.substr(0, e.name.size() - 4);
+#endif              
               patch_list.push_back(e);
 
               c.numberOfPatchesInCatgory ++;

src/common/gui/CPatchBrowser.cpp

@@ -116,7 +116,7 @@ CMouseEventResult CPatchBrowser::onMouseDown(CPoint& where, const CButtonState&
    contextMenu->popup();
    getFrame()->removeView(contextMenu, true); // remove from frame and forget
 
-   return kMouseEventHandled;
+   return kMouseDownEventHandledButDontNeedMovedOrUpEvents;
 }
 
 bool CPatchBrowser::populatePatchMenuForCategory( int c, COptionMenu *contextMenu, bool single_category, int &main_e, bool rootCall )