Add Lines::findChar() to search for starting points in mazes

include/aoc/framework/LinesSolver-impl.hpp

@@ -46,3 +46,9 @@ void LinesSolver<T1, T2>::setCharAt(const Point2& point, const char value)
 {
     lines.setCharAt(point, value);
 }
+
+template <typename T1, typename T2>
+Point2 LinesSolver<T1, T2>::findChar(const char c) const
+{
+    return lines.findChar(c);
+}

include/aoc/framework/LinesSolver.hpp

@@ -33,4 +33,5 @@ class LinesSolver
     bool isInBounds(const Point2& point) const;
     char getCharAt(const Point2& point) const;
     void setCharAt(const Point2& point, const char value);
+    Point2 findChar(const char c) const;
 };