Remove unused `paste` styles.

Ticket: #630
Branch: cleanup/630-remove-paste-styles
Merge branch 'cleanup/630-remove-paste-styles' into develop

Branch: develop
Updated release notes
Merge branch 'develop' of github.com:caktus/django-timepiece into develop
Cleanup image files

- Remove some unused image files
- Rename a few to better represent their content and usage

Ticket: #501
Branch: cleanup/501-images
Merge branch 'cleanup/501-images' into develop

Branch: develop
Mention image cleanup in release notes.

Branch: develop
Fall back to username when user has no first/last name
Merge pull request #633 from caktus/feature/username-fallback

Use username when first/last names are unavailable
Merge branch 'develop' into fix/permanent-tabs-get-params

Conflicts:
	timepiece/templates/timepiece/project/view.html
	timepiece/templates/timepiece/user/view.html