Switch on   First there was an open-air version of Into the Woods at Regent’s Park, then David Suchet and Zoë Wanamaker in All My Sons at the Apollo Theatre, and finally Siân Phillips in Lovesong at the Lyric, Hammersmith. I didn’t leave home, it cost me less than the price of a theatre program, and I may have been watching the beginning of an e-theatre revolution. British-based Digital Theatre films live performance, which it packages and sells through the internet. Through their website you can hire a play, opera or ballet to watch, or download to own. You can…