The Pan-STARRS1 distant z>5.6 quasar survey: more than 100 quasars
  within the first Gyr of the universe
  Luminous quasars at z>5.6 can be studied in detail with the current
generation of telescopes and provide us with unique information on the first
gigayear of the universe. Thus far these studies have been statistically
limited by the number of quasars known at these redshifts. Such quasars are
rare and therefore wide-field surveys are required to identify them and
multiwavelength data are needed to separate them efficiently from their main
contaminants, the far more numerous cool dwarfs. In this paper, we update and
extend the selection for z~6 quasars presented in Banados et al. (2014) using
the Pan-STARRS1 (PS1) survey. We present the PS1 distant quasar sample, which
currently consists of 124 quasars in the redshift range 5.6<z<6.7 that satisfy
our selection criteria. Seventy-seven of these quasars have been discovered
with PS1, and 63 of them are newly identified in this paper. We present
composite spectra of the PS1 distant quasar sample. This sample spans a factor
of ~20 in luminosity and shows a variety of emission line properties. The
number of quasars at z>5.6 presented in this work almost double the quasars
previously known at these redshifts, marking a transition phase from studies of
individual sources to statistical studies of the high-redshift quasar
population, which was impossible with earlier, smaller samples.
