adjust inputs on timeseries processing

[SBFRF]

Right now wavelib.timeSeriesAnalysis1D requires input time to be in datetime. this could be more flexible to be in seconds or maybe dt

example error

fspec, freq = wl.timeSeriesAnalysis1D(timeStamp, ts_componenets.sum(axis=0))
Traceback (most recent call last):
  File "/home/spike/anaconda3/lib/python3.8/site-packages/IPython/core/interactiveshell.py", line 3437, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-34-f8e5146b6583>", line 1, in <module>
    fspec, freq = wl.timeSeriesAnalysis1D(timeStamp, ts_componenets.sum(axis=0))
  File "/home/spike/anaconda3/lib/python3.8/site-packages/testbedutils/waveLib.py", line 462, in timeSeriesAnalysis1D
    assert isinstance(time[0], DT.datetime), 'time must be in datetime'
AssertionError: time must be in datetime