Flatter design on User Page

- Cleanup of the design ( remove border-radius ... )
- Fixed some alignment and width in mobile and lower screen size
Make #update specs consistent

* Use expect syntax
* Avoid lets
* Stub Guardian method used in the controller
Remove duplication in test setup
Add test coverage for #update
Test title updating
Fix ActiveRecord::Associations::CollectionProxy serialization in Rails 4.
Dont call `SiteSetting.uncategorized_category_id` twice
Update server.nl.yml
Update client.nl.yml
shorter message for untranslated strings
FIX issues with quote button

Fix the following issues
- Quote button quotes only one word on iOS
- Quote reply popup should not come up when selecting the text in the ‘reply’ button
revert changes to magnific-popup.scss
some general simplification to modal, menus, etc
merging local with master

Merge remote-tracking branch 'upstream/master'
Merge pull request #1609 from awesomerobot/master

some general simplification to modal, menus, etc
Merge pull request #1608 from sanderdatema/patch-2

Update client.nl.yml
Merge pull request #1607 from sanderdatema/patch-1

Update server.nl.yml
Merge pull request #1606 from vipulnsward/remove_double_calls

Dont call `SiteSetting.uncategorized_category_id` twice
Merge pull request #1602 from salbertson/sa-refactor-users-update-specs

Refactor specs for UsersController#update
Merge pull request #1605 from vikhyat/fix-activerecord-associations-collectionproxy-serialization

Fix serialization of ActiveRecord::Associations::CollectionProxy in Rails 4