logic: Fulltextsearch

* fulltextsearch enabled in sqlite
* fulltextsearch start search with @
* codeview performance improved
* strip sRGB profile from png files to get rid of libpng warning at runtime

src/lib_gui/qt/element/QtSmartSearchBox.h

@@ -32,6 +32,7 @@ class QtSmartSearchBox
 
 public slots:
 	void search();
+	void fullTextSearch();
 
 public:
 	QtSmartSearchBox(QWidget* parent);