set refresh type on eink update in fillMxcfbUpdateData
add more comments
adapt refresh type code in fillMxcfbUpdateData

just to keep consistent with the old refresh type, i.e.
0 for full refresh and 1 for partial
Merge pull request #696 from houqp/new_ui_fix

set refresh type on eink update in fillMxcfbUpdateData
Merge pull request #695 from houqp/new_ui_houqp

return to caller when there is no window to show in UIManager