Merge branch '173-in-selector-elements-allow-unselect' into 'master'

allows unselect in bleeding, mucus, cervix and desire

Closes #173

See merge request bloodyhealth/drip!82

components/cycle-day/select-tab-group.js

@@ -23,7 +23,7 @@ export default class SelectTabGroup extends Component {
             if (isActive) activeStyle = styles.selectTabActive
             return (
               <TouchableOpacity
-                onPress={() => this.props.onSelect(value)}
+                onPress={() => isActive ? this.props.onSelect(null) : this.props.onSelect(value)}
                 key={i}
                 activeOpacity={1}
               >