There are many great mysteries in pop music.  How the heck did Lou Christie move from MGM to Columbia in the wake of “Lightnin’ Strikes” and “Rhapsody in the Rain” and all but disappear? is certainly one of them.  Earlier this year, Ace Records attempted to answer this question with Gypsy Bells: Columbia Recordings 1967, a compendium of the released and unreleased material recorded by the Italian-American falsetto singer during his short and rocky tenure with the label.  Expectedly, it’s a fascinating look at a talented artist who clearly wasn’t eager to…