Changed 'round' method to 'ceil'

Changed to apply to the following rule:

````
0 < time_remaining < 1 -> "Less than a minute"
1 < time_remaining < 2 -> "2 minutes"
2 < time_remaining < 3 -> "3 minutes"
3 < time_remaining < 4 -> "4 minutes"
...
````

Hope this helps for a better understanding of plugin's work.