Almost exactly a year ago, we were publicly yearning for the day when more portable gaming PC makers could ditch Windows in favor of SteamOS (without having to resort to touchy unofficial workarounds). Now, that day has finally come, with Lenovo announcing the upcoming Legion Go S as the first non-Valve handheld to come with an officially licensed copy of SteamOS preinstalled. And Valve promises that it will soon ship a beta version of SteamOS for users to "download and test themselves." As Leno...