Fix issue and compiler warnings

Author: mgreter

src/ast.cpp

@@ -56,8 +56,8 @@ namespace Sass {
     case SASS_COMMA: return ", ";
     case SASS_SPACE: return " ";
     case SASS_DIV: return " / ";
+    default: return "";
     }
-    return "";
   }
 
   /////////////////////////////////////////////////////////////////////////

src/ast_expressions.cpp

@@ -384,12 +384,13 @@ namespace Sass {
     case PLUS: strm << Character::$plus; break;
     case MINUS: strm << Character::$minus; break;
     case SLASH: strm << Character::$slash; break;
+    default: break;
     }
     if (optype_ == NOT) {
       strm << Character::$space;
     }
     strm << operand_->toString();
-    return strm.str();;
+    return strm.str();
   }
 
   /////////////////////////////////////////////////////////////////////////

src/ast_nodes.cpp

@@ -614,7 +614,7 @@ namespace Sass {
     else if (const List* list = isaList()) {
       if (list->empty()) return false;
       sass::vector<sass::string> result;
-      if (list->separator() != SASS_SPACE) {
+      if (list->separator() == SASS_COMMA) {
         for (auto complex : list->elements()) {
           List* cplxLst = complex->isaList();
           String* cplxStr = complex->isaString();
@@ -627,6 +627,9 @@ namespace Sass {
           else return false;
         }
       }
+      else if (list->separator() == SASS_DIV) {
+        return false;
+      }
       else {
         for (auto compound : list->elements()) {
           String* cmpdStr = compound->isaString();

src/inspect.cpp

@@ -663,8 +663,9 @@ namespace Sass {
       return compressed ? "," : ", ";
     case SASS_DIV:
       return compressed ? "/" : " / ";
+    default:
+      return "";
     }
-    return "";
   }
 
   void Inspect::visitList(List* list)