Solves AOJ No. 0086-0089.
Adds EulerGraph to Library.
Modifies Library.
 - static import
 - private constructer
 - array of collection -> List of collection(Graph, AOJ No. 0072)
Adds MagicalSquare to Library.
Solves AOJ No. 0090, 0091.
Modifies EulerGraph null -> emptyList, emptyIntArray.
Modifies AOJ No. 0086.