ENH: refine match mode group result

1.When there are identical materials, try to make the quantity of
materials for each nozzle as similar as possible after grouping.
2.Fix an encoding error

jira:NONE

Signed-off-by: xun.zhang <xun.zhang@bambulab.com>
Change-Id: Iad77d7a995b9c25d004026f409c7e2ecbb8269db
(cherry picked from commit 13d7cd06252678b6b084d17438e99ff808a4191d)
(cherry picked from commit 3cd587d09e066d6c6a27d466b7f663dfd5d674f3)

src/libslic3r/FilamentGroupUtils.hpp

@@ -20,6 +20,9 @@ namespace Slic3r
             unsigned char a = 255;
             Color(unsigned char r_ = 0, unsigned char g_ = 0, unsigned char b_ = 0, unsigned a_ = 255) :r(r_), g(g_), b(b_), a(a_) {}
             Color(const std::string& hexstr);
+            bool operator<(const Color& other) const;
+            bool operator==(const Color& other) const;
+            bool operator!=(const Color& other) const;
         };
 
 
@@ -27,7 +30,8 @@ namespace Slic3r
             Color color;
             std::string type;
             int extruder_id;
-            bool is_extended; // TODO: rename
+            bool is_extended;
+            bool operator<(const FilamentInfo& other) const;
         };