(NORTH ADAMS, Mass.) – Once again indie-rock group Wilco headlines the Solid Sound Festival, which takes place at MASS MoCA on Friday, June 26, to Sunday, June 28, 2015. Among the two-dozen-plus other acts that Wilco has chosen to perform are folk-rock singer-songwriter Richard Thompson, Afrobeat stars King Sunny Ade & his African Beats, downtown-rockers…