implement TextLoader tests, add TestSupport module

src/core/TextLoader.h

@@ -33,10 +33,11 @@ public:
     auto begin() { return m_lines->begin(); }
     auto end() { return m_lines->end(); }
 
-protected:
     typedef std::pair<const uint8_t *, uint32_t> LineIndexPair;
     typedef std::list<LineIndexPair> LineIndexPairList;
     typedef std::shared_ptr<LineIndexPairList> LineIndexPairListRef;
+
+protected:
     int m_line_endings;
     LineIndexPairListRef m_lines;
 };