Chastened by Loss, Jeb Bush Looks Unbeatable in Florida
Jeb Bush, son of former Pres George Bush who lost Florida's gubernatorial race in 1994, seems well on way to completing Republican takeover of state government in fourth most populous state, solidifying party's pre-eminence in South; has formidable lead in polls, no primary opposition and three times finances raised by closest Democratic rival for campaign to succeed retiring Democratic Gov Lawton Chiles, who defeated him by narrow margin in 1994; says he is reaching outside his 'comfort zone' to groups he might have ignored in past, toning down conservative talk, staying away from divisive issues and listening more; photo (M)