LAMOST DR4 v1

### update20170630

There are three corrections having been made in this releasing comparing to the previous internal releasing:

(1) 44,673 spectra have been added into this version, of which the information are included in the list.

(2) 61,785 spectra have been abandoned from this version, which are processed by Du et al. (2017), an important complement to the 2D pipeline. It is mainly caused by the recalculated SNR_r that does not satisfy the released criteria. The information of the rejected spectra are included in the list.

(3) The information have been updated for 2,116,839 spectra due to the corrections of their classification results, redshifts and the errors of redshifts. Specifically, the classification results are corrected for 24,436 spectra. The redshifts are recalculated for 152,721 spectra. And the errors of redshifts are updated for 2,116,000 spectra because of the modification of the error estimation method. The details can be seen in the list.