tox.ini: bump Sphinx to 1.5.5
tox.ini: bump Sphinx to 1.5.5

tzonghao/influxdb-python,influxdata/influxdb-python,BenHewins/influxdb-python,BenHewins/influxdb-python,omki2005/influxdb-python,influxdata/influxdb-python,influxdb/influxdb-python,tzonghao/influxdb-python,omki2005/influxdb-python,influxdb/influxdb-python