fix(instant): fix possible npe in case of filters with undefineds

solves #368
Merge pull request #369 from knalli/bugfix/instant-with-undefined-values

fix(instant): fix possible npe in case of filters with undefineds
fix(refresh): fix bug in refresh if using partial loader
fix($translate): Ensuring that languages will be set based on the order they are requested, not the order the responses come in.
fix($translate): Ensuring that languages will be set based on the order they are requested, not the order the responses come in.
fix($translate): Ensuring that languages will be set based on the order they are requested, not the order the responses come in.
docs(guide/en): Introduce Migration guide chapter

A new version of the Migration guide chapter. Here are listed important notes regarding
an application updating from one version to another.

Fix an error in the Migration guide chapter: You have to call `preferredLanguage` or
`use` method to make it work.
  docs(guide/en): Introduce Migration guide chapter
  fix($translate): Ensuring that languages will be set based on the order they are requested, not the order the responses come in.
fix(instant): $translate.instant(id) does not return correct fallback

Accidently, `$translate.instant(id)` had returned the last found fallback instead of the first found one.
feat(instant): invoke missing handler within `$translate.instant(id)`

Unless a translation was found, the `$missingTranslationHandlerFactory` will now be invoked (was already part of the async part)
Merge pull request #393 from knalli/feature/instant-missing-t9-handler

feat(instant): invoke missing handler within `$translate.instant(id)`
Merge pull request #392 from knalli/bugfix/instant-fallback-iter

fix(instant): $translate.instant(id) does not return correct fallback
Update nav.html

Change links to "angular-translate.github.io"
Update index.html

Change links to "angular-translate.github.io"
Merge pull request #401 from cosminonnet/master

Fix links to new repository
style(): makes jshint happy
chore(*): release 2.0.1