[fix] StyleSheet: shorthand properties

Expand shorthand properties to preserve the one-rule-to-one-style
isolation. Resolve styles like React Native - most specific comes last.
Add support for the hz and vt properties for margin and padding.

Fix #40

examples/components/App.js

@@ -213,7 +213,8 @@ export default class App extends React.Component {
 const styles = StyleSheet.create({
   root: {
     common: {
-      margin: '0 auto'
+      marginVertical: 0,
+      marginHorizontal: 'auto'
     },
     mqSmall: {
       maxWidth: '400px'
@@ -230,7 +231,7 @@ const styles = StyleSheet.create({
     alignItems: 'center',
     flexGrow: 1,
     justifyContent: 'center',
-    borderWidth: '1px'
+    borderWidth: 1
   },
   horizontalBox: {
     width: '50px'

examples/components/MediaQueryWidget.js

@@ -4,7 +4,7 @@ const styles = StyleSheet.create({
   root: {
     alignItems: 'center',
     borderWidth: 1,
-    margin: '10px 0',
+    marginVertical: 10,
     padding: 10,
     textAlign: 'center'
   },