At this point, Spigen SGP's GLAS.t for iPad mini ($58) should come as no surprise -- it's the latest glass screen protector from the company, and its second for iPad mini following GLAS. Whereas that model had painted white or black bezels, this one is completely clear, with just a single opening at the bottom for the iPad mini's Home Button. Like usual, it's crystal clear, and adds 0.4mm on top of the display. Alongside the glass, you get an alcohol…