add tool unix2dos
Update cygwin1.dll to 1.7.27 which is the latest one
Official announcement: http://cygwin.com/ml/cygwin-announce/2013-12/msg00009.html
Mirror we used: http://mirrors.ustc.edu.cn/cygwin/
Warning: DO NOT USE http://mirrors.163.com/cygwin/‎ They have problems
Merge branch 'cygupdate'
Merge remote-tracking branch 'origin'

Conflicts:
	bin/cygwin1.dll