QuizBundle: Working on sortable rounds table

sortable-table.jquery.js from vierbergenlars/snippets@df84845bc6ce1300cd79aa7cf2aeca01cefa94fa
[QuizBundle] Implement sorting backend
[QuizBundle] Add flashmessages for sorting
[QuizBundle] Fix sortable bug

sortable-table.jquery.js from
vierbergenlars/snippets@d01f29b82bd0b0a0afdb8c759abd906361d8cfab
Apply same styles to type=submit, type=button and button
Add icon to cancel button
Merge branch 'dev-quiz-sortables'