Record.adc() truncates, doesn't round

[bemoody]

>>> wfdb.wrsamp('aaa', fs=500, units=['mV'], sig_name=['X'], p_signal=numpy.array([[-1.001],[-0.999],[-0.001],[0.001],[0.999],[1.001]]), adc_gain=[1], baseline=[0], fmt=['16'])
>>> wfdb.rdsamp('aaa')[0]
array([[-1.],
       [ 0.],
       [ 0.],
       [ 0.],
       [ 0.],
       [ 1.]])

Clearly the result should be [[-1],[-1],[0],[0],[1],[1]].