Postgres support

[bettse]

As mentioned in the emails to the elgg-developer list, the team I'm work has added support for Postgres to Elgg 1.5 using ADODB. I plan to attach patches to this ticket using the same plan laid out in my email to the development email group:

1) Submit diffs against trunk for more portable SQL statements (these would be things like inserts using () values () instead of "set").
2) Submit diffs against trunk to correct PHP that results in non-portable statements in SQL (things like value='' when it should be value=0)
3) Submit diffs against trunk to add the adodb library and the necessary changes to have it handle db interaction
4) Submit diffs against trunk for more portable SQL through the use of adodb functions (things like Replace, SQLDate, etc)
5) Submit diffs against trunk to add configuration values to allow Postgres to be selected as a db type, and add a postgres.sql db setup script) 

We worked off the Elgg 1.5 tarball, so my patches will be against that so as to prevent overlap/conflicts in the diff with new changes to the code base. If some patches don't cleanly apply due to larger changes made to the code base, I can do diffs against the SVN on an as-needed basis.

[bettse]

Diff for access.php to modify SQL for portability

[bettse]

Diff for activity.php to modify SQL for portability

[bettse]

Diff for annotations.php to modify SQL for portability

[bettse]

Diff for calendar.php to modify SQL for portability

[brettp]

Moved to ​http://trac.elgg.org/extensions/ticket/291

[brettp]

Ignore previous action.

[cash]

I never realized these patches remove MySQL-specific syntax in favor of standard syntax that would have worked on MySQL. I had always assumed this was making the syntax Postgres specific. Ugh. We should have pulled this in so much earlier.