docs(guide/i18n): fix link to i18n files in the project

Closes #4998
docs(tutorial/step-4): controllers are no longer global functions

The docs did not line up with the codebase / previous steps of the tutorial.

Closes #4988
docs(guide/directive): add note about HTML case-insensitivity

Closes #4719
docs(guide/directive): clarify code example for isolated scopes bindings

Use different names for the attribute on the element (`info`) and the property (`customerInfo`)
on the isolate scope. Before `customer` was used for both which made it harder to understand.

Closes #4825
docs(ngApp): improve description and example
chore(travis): increase disconnect timeout

I still see some disconnection issues with IE9, hopefully this will help a bit.
docs($animate): update the docs explaining enable/disable for specific elements