Update to 0.6.2

Upstream changes:
Version 0.6-2

    o  dbGetQuery do not return NULL.
    o  use registration mechanism to call native routines.

Version 0.5-3

    o  Update the libpq library so that the package can be compiled in new versions of R and macOS.

Version 0.5-2

    o  Support dbBegin() API

version 0.5-1 --2014-02-08

    o  Remove segmentationfault when NULL is passed as host argument.

    o  Conversion routine for raw in R and bytea in PostgreSQL

    o  Use accompanied libpq when either of libpq and header is not found on darwin

Version 0.5 -- 2013-10-12

    o  postgresqlWriteTable: send column names at COPY

    o  System library header search path for OS X 10.9 (Mavericks)

    o  Memory leak was reduced
    o  Close the socket on failure

Version 0.4 -- 2013-03-27

    o  Initial implementation of prepared statement

    o  Use system libpq library when available on OS X (darwin)

    o  Force ISO datestyle for PostgreSQL-R communication by default

    o  Time zone aware Timestamp POSIXct conversion

Version 0.3-3 -- 2012-10-05

    o  Bugfix on dbColumnInfo and others reproducible by gctorture(TRUE)

    o  Do not implicitly make new connections, which interfere with transaction.

    o  Change the notation of the LICENSE

(wen)