revamp by_col_array to accept multifarious arguments
revamp by_col_array to accept multifarious arguments

ljwolf/pysal_core,pastephens/pysal,jlaura/pysal,hasecbinusr/pysal,TaylorOshan/pysal,TaylorOshan/pysal,sjsrey/pysal_core,sjsrey/pysal,TaylorOshan/pysal,pastephens/pysal,ljwolf/pysal,lixun910/pysal,schmidtc/pysal,jlaura/pysal,ljwolf/pysal_core,lanselin/pysal,pedrovma/pysal,hasecbinusr/pysal,jlaura/pysal,lixun910/pysal,hasecbinusr/pysal,ljwolf/pysal,weikang9009/pysal,pastephens/pysal,lixun910/pysal,schmidtc/pysal,ljwolf/pysal,ljwolf/pysal_core,sjsrey/pysal_core,pysal/pysal,sjsrey/pysal_core