move bits functions to separate file + fix missing defaults with disabled program_options on windows

src/bits.cpp

@@ -0,0 +1,15 @@
+#include "bits.hpp"
+
+auto print_bitmap(const uint64_t bitmap, const uint8_t w, const uint8_t h, const std::string& title) -> void {
+    traceln("{}:", title);
+    traceln("{}", std::string(2 * w - 1, '='));
+    for (size_t y = 0; y < w; ++y) {
+        std::cout << "         ";
+        for (size_t x = 0; x < h; ++x) {
+            std::cout << static_cast<int>(get_bits(bitmap, y * w + x, y * h + x)) << " ";
+        }
+        std::cout << "\n";
+    }
+    std::cout << std::flush;
+    traceln("{}", std::string(2 * w - 1, '='));
+}