Independents' day What record industry slump? Independent labels say business has never been better. By Lynne Margolis Eight years ago, Nan Warshaw, Rob Miller, and their Chicago friends were lamenting the dearth of "new and exciting music - music that ignited their passion the way punk and alternative rock had before big record labels and Gap commercials co-opted their sounds. Then they began noticing that several area bands were putting Hank Williams twists on their Nirvana and Elvis Costello influences. So they decided, for kicks, to put out a compilation album of "insurgent country." Warshaw and Miller anted up a...