[c_selection.js] If safari_mobile, get current selection from a previously created global variable
[c_sync.js] ref where the safari_mobile global is used
[c_text_view_comments.js] if safari_mobile update selection also on selectionChange event
[text_view_comments.html] if safari_mobile store a clone of the current selection on each selectionChange
set layout width to 99% to improve display
factorize safari mobile detection code