function made to check which traces of a given DATA structure pass the
SNR test around a given phase

Input:
IN: DATA structure associated to 1 station
SNR_PARAM: structure containing all the necessary parameters (see
init_TESTSNR for more info).
time_phase should be given in matlab datenum
window, LTA, STA should be given in seconds
flag_plot: 0 or 1

Output:
boolean_test:
max_snr:
SNR:

Example:
[a,b,c]=pass_SNRTEST(DATA,SNR_PARAM)