Merge pull request #800 from chrox/new_ui_code

comments for clamping scroll offsets
add scaleByDPI and use it in touchmenu
use scaleByDPI in all widgets
listen swipe gesture in touchmenu
add page counting in touchmenu & bug fix for sub_item_table
more minor cleanup
remove done todo
add exitReader so we can save G_reader_settings properly
forgot to add exitReader at the end
when kpdf.sh start with no argument, it will actuall pass in ""
Merge pull request #803 from houqp/new_ui_houqp

some minor adjustments & finished up touchmenu
bugfix: calculate width of TouchMenu each time when TouchMenu is created
render text with background and foreground 'color'
use inverted font color in toggle switch
Merge pull request #1 from hwhw/new_ui_code

New ui code
add fine tuning of bbox by swipe gesture
add two_finger_pan gesture
make larger valid region for screenshot
change to a formal name
Merge pull request #804 from chrox/touchmenu_fix

bugfix: calculate width of TouchMenu each time when TouchMenu is created