Support async pgsql connections and non-blocking queries

- New functions (each accepts a pgsql $connection resource):

  . pg_connect_poll
  . pg_socket
  . pg_consume_input
  . pg_flush

- Modified functions

  The following functions now additionally return zero if the
  underlying socket is set to non-blocking mode and the send
  operation does not complete immediately. Previously these
  functions returned only boolean TRUE/FALSE and blocked
  execution while polling until all data was sent:

  . pg_send_execute
  . pg_send_prepare
  . pg_send_query
  . pg_send_query_params

- New constants

  Used with pg_connect() to initiate an asynchronous connection
  attempt:

  . PGSQL_CONNECT_ASYNC

  Used with pg_connection_status() to determine the current state
  of an async connection attempt:

  . PGSQL_CONNECTION_STARTED
  . PGSQL_CONNECTION_MADE
  . PGSQL_CONNECTION_AWAITING_RESPONSE
  . PGSQL_CONNECTION_AUTH_OK
  . PGSQL_CONNECTION_SSL_STARTUP
  . PGSQL_CONNECTION_SETENV

  Used with pg_connect_poll() to determine the result of an
  async connection attempt:

  . PGSQL_POLLING_FAILED
  . PGSQL_POLLING_READING
  . PGSQL_POLLING_WRITING
  . PGSQL_POLLING_OK
  . PGSQL_POLLING_ACTIVE

- Polling via returned pg_socket() stream

  pg_socket() returns a read-only socket stream that may be
  cast to a file descriptor for select (and similar) polling
  operations. Blocking behavior of the pgsql connection socket
  can be controlled by calling stream_set_blocking() on the
  stream returned by pg_socket().
Merge branch 'pgsql-async' into PHP-5.6

* pgsql-async:
  Support async pgsql connections and non-blocking queries
UPGRADING (openssl updates)
Update UPGRADING.
Add more descriptions about default_charset and encoding related changes.
Many thanks to Christopher.
Add support for PCRE marks

If a MARK is set then it will be returned in the $matches array
unter key "MARK". If no MARK is used or passed, the key will not
be set.
Fixed typo in UPGRADING and modified php.ini-* description for encoding related changes
Fixed off-by-one in php_url_parse_ex

Change order of condition, previously pointer could be derefrenced before
bound check was done.
Merge branch 'PHP-5.3' into PHP-5.4

* PHP-5.3:
  Fixed off-by-one in php_url_parse_ex

Conflicts:
	ext/standard/url.c
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  Fixed off-by-one in php_url_parse_ex
Fix phpdbg build on FreeBSD

Added missing netinet/in.h header.
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  Fixed off-by-one in php_url_parse_ex
Fixed wrong indentation
Merge remote-tracking branch 'origin/PHP-5.6' into str_size_and_int64_56_backport

* origin/PHP-5.6:
  Fixed wrong indentation
  Fix phpdbg build on FreeBSD
  Fixed off-by-one in php_url_parse_ex
  Fixed typo in UPGRADING and modified php.ini-* description for encoding related changes
  Add support for PCRE marks
  Update UPGRADING. Add more descriptions about default_charset and encoding related changes. Many thanks to Christopher.
  UPGRADING (openssl updates)
  Support async pgsql connections and non-blocking queries

Conflicts:
	ext/pcre/php_pcre.c
	ext/pgsql/pgsql.c