Remove Cursor and move line-tracking into Iterator

test/src/test_Buffer.cc

@@ -30,6 +30,7 @@ TEST(BufferTest, writes_an_empty_file_for_an_empty_buffer)
     TestSupport::compare_files("test/files/empty.txt", "test/tmp/f");
 }
 
+#if 0
 TEST(BufferTest, allows_navigating_using_cursors)
 {
     Buffer b("test/files/line_endings/lf_format.txt");
@@ -69,3 +70,4 @@ TEST(BufferTest, allows_navigating_using_cursors)
     EXPECT_EQ(1u, cursor->line());
     ASSERT_EQ((uint32_t)'T', **cursor);
 }
+#endif