Missing support for percentage widths

[fadookie]

React Native has recently added support for percentage widths.

Tests now fail props validation if a react-native-mock component is passed a percentage width string instead of a number:

Error: Warning: Failed prop type: Invalid prop `style.width` of type `string` supplied to `View`, expected `number`.

[RealOrangeOne]

Ooh, that's a nice improvement. I'm kinda suprised proptype failures cause tests to fail though, but hey it is an actual error i guess.

I plan to spend a large amount of time upgrading the project in the coming weeks, i'll make sure to add this to the list of things to check!