Tidy up the source code

* Replaced push_back calls with emplace_back where applicable.
* Replaced size() == 0 and size() != 0 with empty() and !empty().
* Replaced C style loops for range for loops where applicable.
* Fixed mismatching arg names between function declarations and definitions.
* Replaced NULL and 0 (in the context of pointers) with nullptr.
* Remove unnecessary calls to string::c_str() where applicable.
* Replaced deprecated C headers with proper C++ headers.
* Removed unnecessary null pointer checks when deleting pointers
(deleting a null pointer has no effect).
* Fixed a potential memory leak in apngloader.cpp file.
* Replaced unsafe strcpy with strncpy in the demangle_name function.

src/framework/platform/platformwindow.cpp

@@ -150,8 +150,8 @@ void PlatformWindow::releaseAllKeys()
 
     m_inputEvent.keyboardModifiers = 0;
 
-    for(int i=0;i<4;++i)
-        m_mouseButtonStates[i] = false;
+    for(auto &mouseButtonState: m_mouseButtonStates)
+        mouseButtonState = false;
 }
 
 void PlatformWindow::fireKeysPress()