In the sweltering heat of an early July evening swarms of young Irish hipsters enter the Iveagh Gardens. Amongst the sea of blunt fringes, ratty facial hair and cuffed jeans there are brief pieces of chatter that you would expect from the audience of a Mac Demarco concert. There’s talk of drinking cheap booze and, of course, every other second the word “cigarette” is heard. Without even an ounce of an introduction the first support act, Kirin J Callinan takes to the stage wearing a beret, all black clothing and holding in his hand a fluorescent pink guitar. A few…