feat(ionNavBar,ionHeaderBar): use declarative syntax

Closes #777 
Closes #596 
Closes #477

**New Documentation:**

- [Footer](http://ajoslin.github.io/docs/nightly/api/directive/ionFooterBar)
- [Header](http://ajoslin.github.io/docs/nightly/api/directive/ionHeaderBar)
- [NavBar](http://ajoslin.github.io/docs/nightly/api/directive/ionNavBar)
- [NavBackButton](http://ajoslin.github.io/docs/nightly/api/directive/ionNavBackButton)
- [NavButtons](http://ajoslin.github.io/docs/nightly/api/directive/ionNavButtons)

Also: test count up to 324 :-)