logic: File Manager

* added FileManager that keeps track of the files analyzed by the project. It therefore checks if files get added, updated or deleted from the source- and include folders.
* refactored ASTVisitor::hasValidLocation() and implemented one version that search for the location in the currently parsed file and one that searches in all the project's source files.
* quickfix: switched order in FileManager so that header files are parsed first.
* created folder for helper classes used in tests.
* added test code for FileManager
* adjusted test code for Parser Tests.

src/app/qt/element/QtCodeFile.cpp

@@ -5,7 +5,7 @@
 
 #include "qt/element/QtCodeFileList.h"
 #include "qt/element/QtCodeSnippet.h"
-#include "utility/FileSystem.h"
+#include "utility/file/FileSystem.h"
 
 QtCodeFile::QtCodeFile(const std::string& filePath, QtCodeFileList* parent)
 	: QWidget(parent)

src/app/qt/element/QtCodeFileList.cpp

@@ -5,7 +5,7 @@
 
 #include "data/location/TokenLocationFile.h"
 #include "qt/element/QtCodeFile.h"
-#include "utility/FileSystem.h"
+#include "utility/file/FileSystem.h"
 
 QtCodeFileList::QtCodeFileList(QWidget* parent)
 	: QScrollArea(parent)

src/app/qt/utility/utilityQt.cpp

@@ -5,7 +5,7 @@
 #include <QFile>
 #include <QFontDatabase>
 
-#include "utility/FileSystem.h"
+#include "utility/file/FileSystem.h"
 #include "utility/logging/logging.h"
 
 namespace utility

src/app/qt/view/QtCodeView.cpp

@@ -4,7 +4,7 @@
 
 #include "qt/element/QtCodeFileList.h"
 #include "qt/view/QtViewWidgetWrapper.h"
-#include "utility/FileSystem.h"
+#include "utility/file/FileSystem.h"
 #include "utility/text/TextAccess.h"
 
 QtCodeView::QtCodeView(ViewLayout* viewLayout)