docs(guide/uk,ru): Translate Migration Guide to Russian and Ukrainian

Translate the Migration Guide chapter of the  Guide to Ukrainian and Russian languages.
Merge pull request #416 from DWand/translate-migration-guide

docs(guide/uk,ru): Translate Migration Guide to Russian and Ukrainian langs
docs(guide/en): fix typo
Merge pull request #425 from inetfuture/patch-1

docs(guide/en): fix typo
feat(directive): Support for camel casing interpolation variables.

When using a directive with interpolation variables with camel cased
words (camelCase), there was no nice way to specify the values of the
variables with the `translate-value-*` attributes.

You can specify attributes like this `translate-value-first-name="Glenn"`,
which would work together with this translation string `'Hello {{firstName}}'`.
Merge pull request #430 from tregusti/feature/multi-word-values

feat(directive): Support for camel casing interpolation variables.
fix($translate): use case-insensitive check for language key aliases

When language key aliases are available they are now compared to the browsers locale in a case-insensitive manner.

Closes Issue #431
Merge pull request #434 from mohlendo/case_insensitive_language_key_negotiation

fix($translate): use case-insensitive check for language key aliases
Fixes for a few typos.
Merge pull request #439 from Francisc/canary

doc(): Fixes for a few typos.
fix($translate): if translation exists, use the translated string even if it's empty
Adding Simplified and Traditional Chinese documentation, update the links and enable language chooser for those 2 lanugages.
fix(directive): Make translate-value-* work inside ng-if and ng-repeat

Closes Issue #433
Remove explicit test pin enabling all tests again :hurtrealbad:
Merge branch 'master' into canary

* master:
  chore(*): adds presentation image to readme
Merge branch 'canary' of github.com:angular-translate/angular-translate into canary

* 'canary' of github.com:angular-translate/angular-translate:
  Remove explicit test pin enabling all tests again :hurtrealbad:
docs(*): ensure all dist files contain a license header
Changed Gruntfile:
- extended concat task with banner configuration for each lib_file
- Added exclamation mark to the banner to prevent deletion of banner
  during uglify
- added preserveComments option to uglify task to preserve license
  header.
- registered the concat:banner taskts for each lib file.

Partially resolves #428
chore(*): cleanup obsolete grunt config

Since src/service/default-interpolation.js moved from lib_files.ext to
lib_files.core some time ago, some grunt configuration became obsolete.

- Removed obsolete default_interpolation configuration
- Removed obsolete build:default_interpolation grunt task
chore(Gruntfile): ensure all dist files contain a license header
Changed bower.json:
- added licenses array so that the MIT licence is added to the license headers

Partially resolves #428
fix(package.json): fix repository url