pep8-ify function names

[eric-wieser]

Following on from this comment.

So instead of

task.CfgSampClkTiming(
    source=None,
    rate=1,
    activeEdge=daq.Val_Rising,
    sampleMode=daq.Val_FiniteSamps,
    sampsPerChan=1
)

it would become

task.cfg_sample_clk_timing(
    source=None,
    rate=1,
    active_edge=PyDAQmx.VAL_RISING,
    sample_mode=PyDAQmx.VAL_FINITE_SAMPS,
    samps_per_chan=1
)

This potentially raises the issue that the module name should be PEP8'd as well, becoming the much easier to type pydaqmx