Replace source file viewer with one that actually works.

This is much simpler, custom implementation of a text file viewer. It is
able to perform these two tasks as intended:
- center source view on the selected line,
- highlight that line.

server/TracySourceView.hpp

@@ -0,0 +1,36 @@
+#include <vector>
+
+struct ImFont;
+
+namespace tracy
+{
+
+class SourceView
+{
+    struct Line
+    {
+        const char* begin;
+        const char* end;
+    };
+
+public:
+    SourceView( ImFont* font );
+    ~SourceView();
+
+    void Open( const char* fileName, int line );
+    void Render();
+
+private:
+    void RenderLine( const Line& line, int lineNum );
+
+    ImFont* m_font;
+    const char* m_file;
+    char* m_data;
+    size_t m_dataSize;
+    int m_targetLine;
+    int m_selectedLine;
+
+    std::vector<Line> m_lines;
+};
+
+}