Hands-on review: Kobo Aura One   Kobo&#x27;s latest premium device is the phablet of the ereader world. It feels huge in the hand right now but it may be that in five years time a 7.8-inch screen ereader will be the norm.  Every ereader you can buy right now  including all four products in the ever popular Amazon Kindle range  boasts a 6-inch screen but the Aura One wants to make a major change by offering a larger alternative.  That 7.8-inch screen will feel huge to you if you&#x27;ve been using a…