Pbind v1.0.0

Code breaking:

1. Use PBButton instead of UIButton+Pbind. Futhermore, the PBButton supports the configuration of title, image, background image and background color for different control states.
2. Use formats instead of constraints in PBLayoutMapper. And the constraints is used to support the configuration of Pbind-way constraint format. More details refer to Pbind document.
3. Use next.done for the accomplishment of PBClientAction and PBNotification.
4. Use PBSwitch instead of UISwitch category to implement the PBInput protocol.

Feature:

1. Support configure actions for PBRowMapper.
2. Support configure addRow and deleteRow action for PBCollectionView.
3. Support actions with type notify, watch for NSNotification.
4. Support configure hidden and enabled property for the navigation item defined by nav in Plist.
5. Add enumerators for UIBarButtonSystemItem, UIBarButtonItemStyle and UITableVie
   wRowActionStyle.
6. Support configure an errorRow for PBInput to display error tips just below the input.
7. Add grouped property for PBTableViewController to support configuring the style for the controller. If set as YES use UITableViewStyleGrouped.

Bugfixes:

1. Move the numberOfSectionsInTableView: to PBRowDataSource.
2. Avoid parsing the nested dictionary as a nil value.
3. Avoid the nestedly parsing of views and accessoryView dictionary.

Refactors:

1. Extract PBDataFetcher to fetch data for the view.
2. Extract PBLayoutConstraint to parse the Pbind-way constraint format language.
3. Rename the haveNext method to hasNext in PBAction.
4. Remove the unused references of PBClientMapper.
5. Remove PBRecord.
6. Remove NSArray+PBUtils.

Other:

1. Use PBClient as the default client for debugging while the user does not register any client alias.