add argparse to requirements for py2.6 compatibility
add argparse to requirements for py2.6 compatibility

gbrmachado/treeherder,parkouss/treeherder,tojonmz/treeherder,wlach/treeherder,parkouss/treeherder,parkouss/treeherder,deathping1994/treeherder,gbrmachado/treeherder,gbrmachado/treeherder,edmorley/treeherder,akhileshpillai/treeherder,vaishalitekale/treeherder,KWierso/treeherder,adusca/treeherder,sylvestre/treeherder,adusca/treeherder,sylvestre/treeherder,akhileshpillai/treeherder,tojonmz/treeherder,wlach/treeherder,wlach/treeherder,vaishalitekale/treeherder,vaishalitekale/treeherder,KWierso/treeherder,tojon/treeherder,akhileshpillai/treeherder,jgraham/treeherder,kapy2010/treeherder,vaishalitekale/treeherder,moijes12/treeherder,rail/treeherder,sylvestre/treeherder,edmorley/treeherder,parkouss/treeherder,parkouss/treeherder,moijes12/treeherder,moijes12/treeherder,tojonmz/treeherder,avih/treeherder,adusca/treeherder,sylvestre/treeherder,deathping1994/treeherder,glenn124f/treeherder,tojon/treeherder,vaishalitekale/treeherder,wlach/treeherder,avih/treeherder,tojon/treeherder,deathping1994/treeherder,glenn124f/treeherder,avih/treeherder,sylvestre/treeherder,edmorley/treeherder,rail/treeherder,rail/treeherder,adusca/treeherder,tojonmz/treeherder,deathping1994/treeherder,deathping1994/treeherder,akhileshpillai/treeherder,adusca/treeherder,moijes12/treeherder,KWierso/treeherder,gbrmachado/treeherder,tojonmz/treeherder,jgraham/treeherder,akhileshpillai/treeherder,rail/treeherder,parkouss/treeherder,deathping1994/treeherder,jgraham/treeherder,sylvestre/treeherder,gbrmachado/treeherder,akhileshpillai/treeherder,glenn124f/treeherder,gbrmachado/treeherder,glenn124f/treeherder,jgraham/treeherder,wlach/treeherder,vaishalitekale/treeherder,rail/treeherder,rail/treeherder,KWierso/treeherder,jgraham/treeherder,glenn124f/treeherder,moijes12/treeherder,edmorley/treeherder,kapy2010/treeherder,kapy2010/treeherder,adusca/treeherder,moijes12/treeherder,avih/treeherder,jgraham/treeherder,avih/treeherder,tojonmz/treeherder,kapy2010/treeherder,kapy2010/treeherder,glenn124f/treeherder,wlach/treeherder,tojon/treeherder,avih/treeherder