3 - improve css validation

[usrbowe]

Description

Fix #3
allow only supported react-native stylesheet values.

Example

If we pass: text-align: start, it will get through validation, but it will fail to render, since RN does not support start.

[satya164]

Currently, it's using propTypes to filter things. So you can write a custom version of checkPropTypes to do the filtering instead of hardcoding the list: https://github.com/facebook/prop-types/blob/master/checkPropTypes.js

[usrbowe]

missing validation for Layout Props: https://facebook.github.io/react-native/docs/layout-props

[usrbowe]

possible better to check against value validation defined here: https://github.com/facebook/react-native/blob/master/Libraries/Components/View/ViewStylePropTypes.js (for text, view)

Update:
Can't directly use PropTypes itself, so custom version of checkPropTypes would be way to go.