Always fully clear temporary directories

Make sure TempDirectory dtor always removes Poedit's temporary directory
completely, without errors. There were two subtle bugs in the old code:

1. Poedit would try to rmdir the directory even with --keep-temp-files.
This would fail because the files weren't deleted.

2. If something created unexpected extra files, rmdir would fail too.

Fix both by recursively deleting the directory with its content, instead
of doing the same thing manually, but only for recognized files. As a
bonus, make the code slightly simpler.

See umpirsky/Twig-Gettext-Extractor#12

src/utility.cpp

@@ -135,40 +135,33 @@ TempDirectory::TempDirectory() : m_counter(0)
 
 TempDirectory::~TempDirectory()
 {
-    if ( m_dir.empty() )
-        return;
-
     Clear();
-
-    wxLogTrace("poedit.tmp", "removing temp dir %s", m_dir.c_str());
-    wxFileName::Rmdir(m_dir);
 }
 
 void TempDirectory::Clear()
 {
+    if ( m_dir.empty() )
+        return;
+
     if ( ms_keepFiles )
     {
         wxLogTrace("poedit.tmp", "keeping temp files in %s", m_dir.c_str());
         return;
     }
 
-    for ( wxArrayString::const_iterator i = m_files.begin(); i != m_files.end(); ++i )
-    {
-        if ( wxFileName::FileExists(*i) )
-        {
-            wxLogTrace("poedit.tmp", "removing temp file %s", i->c_str());
-            wxRemoveFile(*i);
-        }
-    }
+    wxLogTrace("poedit.tmp", "removing temp dir %s", m_dir.c_str());
+    wxFileName::Rmdir(m_dir, wxPATH_RMDIR_RECURSIVE);
+
+    m_dir.clear();
 }
 
 wxString TempDirectory::CreateFileName(const wxString& suffix)
 {
+    wxASSERT( !m_dir.empty() );
     wxString s = wxString::Format("%s%c%d%s",
                                   m_dir.c_str(), wxFILE_SEP_PATH,
                                   m_counter++,
                                   suffix.c_str());
-    m_files.push_back(s);
     wxLogTrace("poedit.tmp", "new temp file %s", s.c_str());
     return s;
 }

src/utility.h

@@ -195,7 +195,6 @@ class TempDirectory
 private:
     int m_counter;
     wxString m_dir;
-    wxArrayString m_files;
 
     static bool ms_keepFiles;
 };