[ui:cwd] for touch device, open contextmenu by long-tap
[ui:cwd] support cwd contextmenu with long-tap for touch devices
[ui:cwd] correction of longtap event handling
[ui:cwd,tree] correction for iOS touch devices
[ui:cwd] optimize context menu operation in list view
Merge branch '2.x' into 2.1

Conflicts:
	js/ui/cwd.js
Merge branch '2.1' into 2.1_n