Attention: This application require this permission in order to modify the display timeout setting:
android.permission.BIND_DEVICE_ADMIN

And you can remove the device administrator with the following steps:
Go to SETTINGS->Location and Security-> Device Administrator and deselect the admin which you want to uninstall.

Click "NEVER TIMEOUT" to set screen timeout to never.
Click "RESTORE ORIGINAL SETTING" to restore the screen timeout setting.
Simple. Easy. Supreme.
No Screen Off
Timeout Never
Never Suspend