New Features and bugs fix.

1.Restructure classes.
2.Prefix for each API in category, avoid conflict with other frameworks.
3.Change the default value behavior of property
“jz_navigationBarBackgroundAlpha”, If you have not set this property
then the value will be as same as the property of navigation
controller, so you need not set this property to every view controllers
when your expect value is not 1.0f.
4.New property for navigation controller operation. See demo for usage.
5.New property of navigation controller
“jz_previousVisibleViewController”, could use this to do any logic
during navigation transition in any method you want, like
"viewWillAppear:".
6.

• 6.1 Change the behavior of “navigationBarTintColor” : “If have not set
this property then the value will be the current navigation bar
  barTintColor dynamically. Set it to "nil", when you expect a system
  default color.”.
• 6.2 Deprecated property “interactivePopedViewController”, use
  “jz_previousVisibleViewController” instead.
• 6.3 Remove useless param in
  “setJz_interactivePopGestureRecognizerCompletion” block.
  7.1 Fix pop gesture conflict with other gestures.

  7.2 Fix bugs.
  7.3. New interface “jz_setInteractivePopGestureRecognizerCompletion:”.
  7.4. New block type in navigation transition completion callback.