Zoom-in and Zoom-out icons should be disabled when reaching maximum and minimum level

[ahsanultanvir]

Zoom-in and Zoom-out icons should be disabled when reaching maximum and minimum level.
For example:

• if the maximum zoom level is 10, then then '+' icon should be disabled when zoom reaches to level 10.
• if the minimum zoom level is 1, then then '-' icon should be disabled when zoom reaches to level 1.
• cursor property should be not-allowed for these cases for more visibility.