It’s now been almost 13 years since nearly 70% of D.C. voters approved an initiative enacting a medical marijuana law in the nation’s capital, though you’d be forgiven if you hadn’t noticed. An obscure budget provision known as the “Barr Amendment” stalled implementation for years, and when it was finally removed (after MPP hired Congressman Barr to help defeat his own amendment) in late 2009, the D.C. Council went to work passing an amendment to the law making the proposed program much more restrictive.…