set bgcolor to gray in cropping dialog
set manual cropping if bbox exists
set widget spacing according to screen DPI
make larger default page margin
fix whitespaces
Merge pull request #771 from chrox/kopt-bbox-fix

set manual cropping if bbox exists in koptinterface
Merge pull request #772 from houqp/new_ui_houqp

fix whitespaces
record multiple slots for multi-touch input

for now, only slot 0 is parsed, the rest are ignored.
Merge pull request #774 from houqp/new_ui_houqp

record multiple slots for multi-touch input
add multiple slots in gesture detector
So that gesture detecting in one slot won't block gestures in the other slots.
cleanup: use local variables in time arithmetic
add gesture emitting rate in GestureRange
set rate in pan GestureRange in bbox widget
add direction and distance in pan/swipe gesture
add flipping mode in pdf/djvu reader
By tapping on the upper left corner of the reader one can toggling flipping mode on/off.
In flipping mode swiping right/down and left/up  will paging backward and forward
accordingly with pages proportional to swiping distance.
add resources files for page flipping
Merge pull request #776 from chrox/mt_hold

add multiple slots in gesture detector
save/restore view mode and embedded css mode
Merge pull request #777 from chrox/cre-option-fix

save/restore view mode and embedded css mode
clamp used bbox to page dimension