Release v1.2.0 as it appears on CRAN

• Add a session.timezone parameter to dbConnect and src_presto which
  defaults to UTC. This affects the timestamps returned for Presto data types
  "TIMESTAMP". We handle the ambiguity by assigning a time zone to every
  POSIXct column returned. Note that if you are doing as.character() directly
  on these columns, the values you obtain will be different from what happened
  before.
• Fix the way we handle zero row multiple column query results. This will
  affect LIMIT 0 queries specifically.