Duplicates

Created by: yookoala

Corresponding to the closed bug #92 of libcangjie.

Some user testing revealed that we don't properly eliminate duplicate characters returned to the user.

This is especially bad for Quick users.

A few examples...

• a query for m*e will return: 汞歿泵玻夏破球豉瑕碌碌酸憂臻豭璦霞覆
• a query for o*e will return: 伋侵俊隻假氯氯飯傻優雙餿饅伎汆汆俅复
• a query for l*j will return: 蚪蚌牌牌蜂幛裨蝌輩褲蟀蟑蟬虷蜱幝蝻褌

It is considered to fix this in libcangjie side. However, after discussion, we've decided to fix this in ibus-cangjie.