Restructure "src/" folder

Moving files from the "src/" folder into "src/legacy", "src/macro-core",
and "src/utils" was necessary as it was becoming a bit too cluttered.

src/utils/resizing-text-edit.cpp

@@ -0,0 +1,31 @@
+#include "resizing-text-edit.hpp"
+
+ResizingPlainTextEdit::ResizingPlainTextEdit(QWidget *parent,
+					     const int scrollAt,
+					     const int minLines,
+					     const int paddingLines)
+	: QPlainTextEdit(parent),
+	  _scrollAt(scrollAt),
+	  _minLines(minLines),
+	  _paddingLines(paddingLines)
+{
+	QWidget::connect(this, SIGNAL(textChanged()), this,
+			 SLOT(ResizeTexteditArea()));
+}
+
+void ResizingPlainTextEdit::ResizeTexteditArea()
+{
+	QFontMetrics f(font());
+	int rowHeight = f.lineSpacing();
+	int numLines = document()->blockCount();
+	if (numLines + _paddingLines < _minLines) {
+		setFixedHeight(_minLines * rowHeight);
+	} else if (numLines + _paddingLines < _scrollAt) {
+		setFixedHeight((numLines + _paddingLines) * rowHeight);
+	} else {
+		setFixedHeight(_scrollAt * rowHeight);
+	}
+
+	adjustSize();
+	updateGeometry();
+}