add support for third-party keyboard(fix #148)

Author: alexazhou

TPKeyboardAvoiding/UIScrollView+TPKeyboardAvoidingAdditions.m

@@ -61,12 +61,15 @@ - (void)TPKeyboardAvoiding_keyboardWillShow:(NSNotification*)notification {
 
     state.keyboardRect = keyboardRect;
     state.keyboardVisible = YES;
-    state.priorInset = self.contentInset;
-    state.priorScrollIndicatorInsets = self.scrollIndicatorInsets;
 
-    state.priorPagingEnabled = self.pagingEnabled;
+    if ( !state.keyboardVisible ) {
+        state.priorInset = self.contentInset;
+        state.priorScrollIndicatorInsets = self.scrollIndicatorInsets;
+        state.priorPagingEnabled = self.pagingEnabled;
+    }
+
     self.pagingEnabled = NO;
-    
+        
     if ( [self isKindOfClass:[TPKeyboardAvoidingScrollView class]] ) {
         state.priorContentSize = self.contentSize;