add target output file support for reporter (color and non-color version)

import radical.utils as ru
r = ru.Reporter (title   = 'motto',
                 targets = ['>/tmp/nc_write',
                            '>>/tmp/nc_append',
                            '>&/tmp/c_write',
                            '>>&/tmp/c_append',
                            '/tmp/default',
                            'stdout'])

r.header  ('nothing')
r.info    ('is')
r.ok      ('ever')
r.warn    ('easy')
r.error   ('...')