update tooltip.cpp, cancel the private head file dependence
test code for pre-reading
All image decoding move to pre-reading thread; Add: show file in Explorer
Add: image scale mode and align mode
Add: move image content through keyboard
Refactor ImageViewer, use VelociTracker to process mouse event of it
Change libexif and ImageReader into easyexif and ImageHeader; Add raw image support(not perfert).
Bugfix: fix bug with VelocatyTracker occurred on mouse move
Merge pull request #1 from yuezhao/master

update to new from yuezhao