Regeneron’s (NSDQ:REGN) top two execs, CEO Dr. Leonard Schleifer and CSO Dr. George Yancopoulos, are two of the best-paid in biotech.  Two proxy advisory service firms, Glass Lewis (San Francisco, Calif.) and Institutional Shareholder Services (Rockville, Md.), are balking at Regeneron’s executive pay program and practices.  The two firms are urging shareholders to oust George…