Analyzer: properly require settings parameter

there are non-optional values in the `Settings` struct, accordingly all
of the callers must pass it along. it was wrong to default it to an
empty struct, that shouldn't even compile (but somehow does with MSVC...
CLion correctly complains in the IDE).

Author: rursprung

include/banana-lib/lib.hpp

@@ -143,7 +143,7 @@ namespace banana {
             cv::Scalar const filter_upper_threshold_color{177, 255, 255};
         };
 
-        explicit Analyzer(Settings settings = {});
+        explicit Analyzer(Settings settings);
 
         /**
          * Analyse an image for the presence of bananas and their properties.

test/banana-lib-test.cpp

@@ -11,7 +11,9 @@
 #define ASSERT_SAME_MAT(a,b) ASSERT_EQ(cv::Scalar(), cv::sum(a != b))
 
 #define GET_RESULT(path, num_expected)                            \
-    banana::Analyzer const analyzer;                              \
+    banana::Analyzer const analyzer{{                             \
+        .pixels_per_meter = 1,                                    \
+    }};                                                           \
     auto const image = cv::imread(path);                          \
     auto const result_ = analyzer.AnalyzeAndAnnotateImage(image); \
     ASSERT_TRUE(result_);                                         \
@@ -20,14 +22,18 @@
     do {} while(false)
 
 TEST(GeneralBananaTestSuite, FailOnNonExistingImage) {
-    banana::Analyzer const analyzer;
+    banana::Analyzer const analyzer{{
+        .pixels_per_meter = 1,
+    }};
     auto const image = cv::imread("non-existent-image.jpg");
     auto const result = analyzer.AnalyzeImage(image);
     ASSERT_FALSE(result);
 }
 
 TEST(BananaContourFinderTestSuite, AnalyzeEmptyPicture) {
-    banana::Analyzer const analyzer;
+    banana::Analyzer const analyzer{{
+        .pixels_per_meter = 1,
+    }};
     auto const image = cv::imread("resources/test-images/empty.jpg");
     auto const result = analyzer.AnalyzeImage(image);
     ASSERT_TRUE(result);