restrict highlight in current page area
This should fix #588.

Highlight in multiple pages is too complicated and requires large
code refactoring and will not be considered for now.
tap to clear selected text too
This should fix #589.
update buildin font names
touch menu entry now responses hold gestures
confirmbox with button table
hold on font menu entry to set default font
Merge pull request #683 from chrox/master

restrict highlight in current page area