added test for merging files.
added test for merging files.

devkev/mtools,parkhyeonghwa/mtools,corymintz/mtools,aerrami/mtools,aerrami/mtools,rueckstiess/mtools,gormanb/mtools,ces0712/mtools,ces0712/mtools,parkhyeonghwa/mtools,corymintz/mtools,ces0712/mtools,tomzhang/mtools,devkev/mtools,corymintz/mtools,yaowenqiang/mtools,gormanb/mtools,yaowenqiang/mtools,devkev/mtools,parkhyeonghwa/mtools,gormanb/mtools,rueckstiess/mtools,aerrami/mtools,yaowenqiang/mtools,tomzhang/mtools,tomzhang/mtools