Fix a bug on end of sentence detection.

Given non alphabet input sentence with partial sentence as follow,

EndOfSentenceDetector should detect 5 as the end of sentence postion.

こんにちは．きょうは

But the EndOfSentenceDetector wihtout this patch detects the end position as 10.
Simplify test sample sentences
Merge pull request #231 from takahi-i/fix-sentence-split-bug

Fix sentence split bug