message: Raised onPress event on tab bar item
diff: #import "NVSegmentedControlView.h"
  +#import "NVTabBarItemView.h"
  @implementation NVSegmentedControlView
  {
  - (void)didMoveToWindow
  {
  [super didMoveToWindow];
  - [self selectTab];
  + [self selectTab:false];
  }
  - (void)tabPressed
  {
  _selectedIndex = self.selectedSegmentIndex;
  - [self selectTab];
  + [self selectTab:true];
  }
  -- (void)selectTab
  +- (void)selectTab:(Boolean) press
  {
  NSInteger tabBarIndex = 1 - [self.superview.subviews indexOfObject:self];
  UIView* tabBar = [self.superview.subviews objectAtIndex:tabBarIndex];
  for(NSInteger i = 0; i < [tabBar.subviews count]; i++) {
  - [tabBar.subviews objectAtIndex:i].alpha = (i == _selectedIndex ? 1 : 0);
  + NVTabBarItemView *tabBarItem = (NVTabBarItemView *) [tabBar.subviews objectAtIndex:i];
  + tabBarItem.alpha = (i == _selectedIndex ? 1 : 0);
  + if (press && i == _selectedIndex && !!tabBarItem.onPress) {
  + tabBarItem.onPress(nil);
  + }
  }
  }
  