Moved files up to root directory

Working on restructuring things to more closely match up with
the layout of puppetlabs-mysql.
Working version of postgresql::server

This is a first working version of postgresql::server.
It includes a very simple test manifest, which has
been tried out on CentOS6 and Ubuntu 10.04; initial
tests were successful both from a clean state and
for subsequent runs.

Includes a new fact called 'postgres_default_version',
which detects what the default version of postgres is
for a given OS.  This is needed because some of the
commands and directory names include this version string.

Current implementation *only* supports managing the
system default version; in the future it would be nice
to allow the user to explicitly specify a postgres version,
but that isn't yet supported.

The "postgresql::server" class includes a call to postgres's
initdb command on redhat systems, because they don't do
this automatically when the package is installed.
Improve configuration for initial postgres install

This commit adds some configuration management for
postgres, to allow users to get a more complete
setup from their initial install.  Prior to this
commit, we were basically only ensuring that the
package was installed and the service was running.

Now, we support limited configuration for the
pg_hba.conf file to enable md5 authentication for
remote hosts, and for the postgresql.conf file
to specify the listener addresses where TCP
connections should be accepted.  Without these
two changes the initial postgres configuration
doesn't allow *any* connections from outside of the
local host.

This commit also adds an option for opening up the
postgres port in the firewall on redhat-based systems,
and an option to allow setting the password for the
'postgres' database user.

As of this commit, this module now has dependencies
on puppetlabs-stdlib (version > 2.3.4, which includes
the new 'match' parameter for the 'file_line' resource
type), and on puppetlabs-firewall.
Bring database, database_user, and database_grant into alignment with mysql module

Renamed a few files and made some tweaks to try to get
database_grant, database_user, and database types into
a state where they work very similarly to the ones in
the mysql module.  Also introduced a "postgresql_password"
function that can be used to generate an md5 password
hash for a postgres user.
Add postgresql::db convenience type, improve security

This commit adds a postgresql::db type for convenience;
it mirrors the 'db' type from the mysql module, which
allows you to create a database instance and user plus
grant privileges to that user all in one succint
resource.

This commit also improves security in the following ways:

* Revoke "CONNECT" privilege from the 'public' role for
  newly created databases; without this, any database
  created via this module will allow connections from
  any database user, and will allow them to do things
  like create tables.

* Change to a 'reject'-based policy for dealing with
  remote connections by the postgres user in pg_hba.conf.
  Prior to this commit, if you tried to restrict access
  to the postgres user by IP, the rule would simply not
  match for disallowed IPs; then it would fall through
  to the rule for "all" users, which could still match
  and thus allow the postgres user to connect remotely.
Fix for debian 6 service name

It turns out that Ubuntu and Debian have different names
for the postgres service; this fix makes the module
compatible with debian 6.