Misc performance tweaks.

modules/juce_audio_formats/codecs/juce_CoreAudioFormat.cpp

@@ -172,7 +172,7 @@ struct CoreAudioFormatMetatdata
         }
 
         if (tempoSequence.getDataSize() > 0)
-            midiMetadata.set ("tempo sequence", tempoSequence.toString());
+            midiMetadata.set ("tempo sequence", tempoSequence.toUTF8());
     }
 
     static double getTempoFromTempoMetaEvent (MidiMessageSequence::MidiEventHolder* holder)
@@ -217,7 +217,7 @@ struct CoreAudioFormatMetatdata
         }
 
         if (timeSigSequence.getDataSize() > 0)
-            midiMetadata.set ("time signature sequence", timeSigSequence.toString());
+            midiMetadata.set ("time signature sequence", timeSigSequence.toUTF8());
     }
 
     //==============================================================================

modules/juce_core/json/juce_JSON.cpp

@@ -316,7 +316,7 @@ private:
             buffer.appendUTF8Char (c);
         }
 
-        result = buffer.toString();
+        result = buffer.toUTF8();
         return Result::ok();
     }
 };
@@ -526,7 +526,7 @@ String JSON::toString (const var& data, const bool allOnOneLine)
 {
     MemoryOutputStream mo (1024);
     JSONFormatter::write (mo, data, 0, allOnOneLine);
-    return mo.toString();
+    return mo.toUTF8();
 }
 
 void JSON::writeToStream (OutputStream& output, const var& data, const bool allOnOneLine)

modules/juce_core/streams/juce_InputStream.cpp

@@ -175,7 +175,8 @@ String InputStream::readString()
         }
     }
 
-    return String::fromUTF8 (data, (int) i);
+    return String (CharPointer_UTF8 (data),
+                   CharPointer_UTF8 (data + i));
 }
 
 String InputStream::readNextLine()

modules/juce_gui_basics/widgets/juce_TextEditor.cpp

@@ -2385,7 +2385,7 @@ String TextEditor::getText() const
     for (int i = 0; i < sections.size(); ++i)
         sections.getUnchecked (i)->appendAllText (mo);
 
-    return mo.toString();
+    return mo.toUTF8();
 }
 
 String TextEditor::getTextInRange (const Range<int>& range) const
@@ -2414,7 +2414,7 @@ String TextEditor::getTextInRange (const Range<int>& range) const
         index = nextIndex;
     }
 
-    return mo.toString();
+    return mo.toUTF8();
 }
 
 String TextEditor::getHighlightedText() const

modules/juce_gui_extra/code_editor/juce_CodeDocument.cpp

@@ -522,7 +522,7 @@ String CodeDocument::getTextBetween (const Position& start, const Position& end)
         }
     }
 
-    return mo.toString();
+    return mo.toUTF8();
 }
 
 int CodeDocument::getNumCharacters() const noexcept