Fixes bugs with authentication, header, and performance.

[sophiabersani]

Stories:

https://www.pivotaltracker.com/story/show/120195889
https://www.pivotaltracker.com/story/show/120106289
https://www.pivotaltracker.com/story/show/120192313

• Fixes issue with missing Header titles.
• Fixes an issue with authentication.
• Updates Realm package version to fix a memory leak.
• Fixes some slowdowns caused by the 3rd party Drawer being wired up with setState() methods.
  • Note: While the fix takes care of some of the overdone re-rendering caused by this component, the app is still unacceptably slow when using this menu.
  • These slowdowns might be being caused by Realm instead of the component, as they seem to happen when a View needs to load data from it. This is happening with both debuggers ON and OFF, updating the package helped with some of it, but it's still far from smooth.

[appden]

@gbersani I work on the Realm React Native binding. Would you mind telling me how I can reproduce these slowdowns in this app so I can investigate further? We definitely recognize that running in Chrome debug mode slows things down given how it has to work (discussed in realm/realm-js#390), but it shouldn't be introducing any slowdowns into your app when not debugging. Thanks!