conditional availability of get_all based on pypy or cpython, also is_tracked was added in 2.7, so making get_all work with 2.6
conditional availability of get_all based on pypy or cpython, also is_tracked was added in 2.7, so making get_all work with 2.6

suranap/boltons,markrwilliams/boltons,doublereedkurt/boltons,neuropil/boltons,mgaitan/boltons,kevinastone/boltons,zeroSteiner/boltons,siemens/boltons