modify：修复在索引为0位置，往左划，索引错误的bug；优化setdataarr后pagecontrol控件也置0

DZXCarouselView/Classes/DZXCarouselView.m

@@ -237,7 +237,7 @@ static BOOL isScrolling = NO;
 -(void)scroll {
     if (_dataArr.count > 1) {
         if (_isLast) {
-            self.currentIndex = (_currentIndex - 1)%_dataArr.count;
+            self.currentIndex = (_currentIndex - 1 + _dataArr.count)%_dataArr.count;
         }else{
             self.currentIndex = (_currentIndex + 1)%_dataArr.count;
         }
@@ -248,7 +248,7 @@ static BOOL isScrolling = NO;
 }
 //更新内容
 - (void)updateViewData {
-    [self addProperty:_dataArr[(_currentIndex-1)%_dataArr.count] toObj:_lastV];
+    [self addProperty:_dataArr[(_currentIndex-1+_dataArr.count)%_dataArr.count] toObj:_lastV];
     [self addProperty:_dataArr[_currentIndex] toObj:_currentV];
     [self addProperty:_dataArr[(_currentIndex+1)%_dataArr.count] toObj:_nextV];
     
@@ -362,7 +362,7 @@ static BOOL isScrolling = NO;
     if (_currentIndex < 0 || _currentIndex >= _dataArr.count) return;
     NSInteger willShowIndex;
     if (isLast) {
-        willShowIndex = (_currentIndex - 1)%_dataArr.count;
+        willShowIndex = (_currentIndex - 1 + _dataArr.count)%_dataArr.count;
     }else{
         willShowIndex = (_currentIndex + 1)%_dataArr.count;
     }
@@ -418,6 +418,9 @@ static BOOL isScrolling = NO;
     //页面展示block（第一次进来）
     _pageWillShowBlock(0, _dataArr[0]);
     _pageShowBlock(0, _dataArr[0]);
+    if (_carouselConfig.showPageControl) {
+        _pageControl.currentPage = 0;
+    }
 }
 
 @end