Modified itemize regExp rules

Signed-off-by: Watanabe, Kimitaka <kimitaka@logic.cs.tsukuba.ac.jp>
Support strikeout

Signed-off-by: Watanabe, Kimitaka <kimitaka@logic.cs.tsukuba.ac.jp>
Remove line-end space character

Signed-off-by: Watanabe, Kimitaka <kimitaka@logic.cs.tsukuba.ac.jp>