Cody Weaver a37d4a4f3a
[Tabs] Fix an example bug (#5106)
This changes adds a `MDCAppBarColorThemer` and `MDCAppBarTypographyThemer` to the example. Previously there was a bug where the app bar wasn't the same color as the tab bar this addresses that.

Related to #2408  

| Before | After |
| ------- | ------- |
|![simulator screen shot - iphone x - 2018-09-12 at 11 07 36](https://user-images.githubusercontent.com/7131294/45434318-23f10c80-b67c-11e8-8345-079a4a87b4c8.png)|![simulator screen shot - iphone x - 2018-09-12 at 10 53 44](https://user-images.githubusercontent.com/7131294/45434323-281d2a00-b67c-11e8-9aba-6d6c3734680c.png)|
2018-09-12 11:34:51 -04:00
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