Adding HTC Nexus 9 recognition

Adding regex for Nexus 9 tablet

UA String:
>Mozilla/5.0 (Linux; Android 5.0; Nexus 9 Build/LRX21R) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.143 Mobile Crosswalk/7.36.154.13 Safari/537.36