A wide-ranging collection of arts groups and cultural leaders will meet this weekend in Baltimore for the city’s second annual summit meeting on the arts. Mayor Martin O’Malley hosted the first meeting last year, which was billed as a citywide brainstorming session, and which drew 300 artists and activists. This year’s event will focus on ways to make up the national shortfall in arts funding, the future of private giving to the arts, and the omnipresent issue of how to draw out a city’s “creative class.”