Update README.md
Add Turkish (tr) support. Fixes #4
Update topic trees and add Turkish topic tree

Test Plan:
- Load Turkish app by setting system locale and starting the app
Update version to 1.1 in preparation for the next release

Test Plan:
- None
Remove unused topic-tree-bn.json file after it is minified
Merge branch 'master' of https://github.com/bbondy/khan-academy-fxos