fix #1880 by using a simple trick to fix widow words

fix #1880 by using a simple trick to fix widow words
Before:
![screen shot 2014-11-03 at 17 47 45](https://cloud.githubusercontent.com/assets/40213/4886082/570a7f70-6379-11e4-8093-6199871e8748.png)


After:
![screen shot 2014-11-03 at 14 59 44](https://cloud.githubusercontent.com/assets/40213/4886081/549ef93c-6379-11e4-95a7-66e14995b84a.png)
Doesn't `TextUtils.concat` (which is called by `replaceCharacter` below) already take care of the spans?