feat: add int slider, fix float slider rang

src/Engine/Parameter/Parameter.h

@@ -14,7 +14,9 @@ public:
 
     bt::floatT evalFloat(unsigned int index=0) const;
     bt::String evalString(unsigned int index=0) const;
+    bt::intT evalInt(unsigned int index=0) const;
     
+    void setInt(bt::intT value, unsigned int index=0);
     void setFloat(bt::floatT value, unsigned int index=0);
     void setString(bt::String value, unsigned int index=0);
 
@@ -23,6 +25,7 @@ private:
     Template template_;
     std::vector<bt::floatT> floatValues_;
     std::vector<bt::String> stringValues_;
+    std::vector<bt::intT> intValues_;
 
 };
 }