Merge pull request #6 from saaros/master

PostgreSQL 9.2 support
pgmemcache: fix arguments and return types in guc functions.

Also removed the custom default value check function which was not supposed
to do anything, but sometimes returned false values to the caller as the
function is supposed to return a boolean value (1 byte) but returned a
pointer instead.
Merge pull request #7 from saaros/fix_guc_callbacks

pgmemcache: fix arguments and return types in guc functions.
pgmemcache: make it a real extension

Recommend postgresql 9.1 or newer versions which support the extension
mechanism.  It's still possible to install pgmemcache on older server
versions, but it requires some manual work.
Merge pull request #9 from saaros/extension

pgmemcache: make it a real extension
sql: update version to 2.1 and add STRICT to all functions

This makes the functions consistent (for example incr used to have STRICT
while decr didn't) and fixes crashes on various functions which did not
check NULL arguments.
doc: release notes for version 2.1
Merge pull request #10 from saaros/version-2.1.0

Version 2.1.0