Saturday, August 25 is the 100th anniversary of Leonard Bernstein's birth.  During the upcoming weekend, Tanglewood, the Boston Symphony's Berkshires summer home where "Lenny's" conducting career began as a student in 1940 and ended with his last concert months before his death in 1990, and London's BBC Proms offer non-stop Bernstein.  The classical music streaming service Medici.tv is offering a week of Bernstein archival footage and documentaries.  For those who want to keep the music going there is Sir Antonio Pappano and the The Santa Cecilia Orchestra's new release of Lenny's three symphonies.  Additionally, since musical milestones are aimed at