Update README.md

Correct Name utag to uTag.
Add TargetUsers.md & UseCases.md
Add 4 use cases
Add Requirements, update TargetUsers & UseCases
Add very basic prototype for frontend UI
Update Requirements
Add project boilerplate

- angular app with node, grunt & bower
- php laravel framework with composer
- some basic functionality as poc
Change file permissions from 644 to 755
Include feature/design for further development
Replace yeoman with slush, i.e. grunt with gulp
Add inital DB script & image of relational model
Update db script to drop the db only if it exists
Add database-migrations for laravel-framework
Update TagsTableSeeder to real seeder
Update file permissions for Windows compatibility
Rename resource to thing in migrations
Add ThingsTableSeeder, update DatabaseSeeder
 so 'php artisan db:seed' works without class parameter
Rename "resource" to "things", "tag" to "tags"
Add ThingTagTableSeeder
Add ThingsController to list all things