FIX: Prevent negative font sizes

[rolandschuetz]

Fixes #66

[hassamarifdev]

facing same problem

[hassamarifdev]

tabSize is 0 in the start and then it increases that's why it gives an error. please correct the code here
<Text style={{ textAlign: "center", paddingBottom: 8, // fontSize: tabSize - 4 fontSize: 20 }} > {category.symbol} </Text>

I just changed the fontSize and it works just fine.. I hope it will help.

[rolandschuetz]

@hassamarifdev did you try and get these arrows with my pull request?

As you can see in my code change, I am making sure that there is no negative value.