NeoTerm v1.2.3

Feature：Create new color scheme in app（Settings->Customization->Install->New Color Scheme）
Feature：Add builtin user scripts（extract-archive and open-in-vim）
Feature：PageUp and PageDown support long press
Improve：Package source dialog
Improve：Session close message
Fix：Crash when opening help link
Fix：Notification with new API.
Fix：Package source cache file
Fix：ActionMode didn't show overlay on Android 5.x
Fix：Toolbar color
Fix：Uncancelable dialog while apt is running.