Changes throughout Moodle to remove any reserved words from the

Moodle tables.

ie user -> userid in many tables, plus in user_students
   start -> starttime and end -> endtime

I've just done all this as carefully as I could ... I don't think
I missed anything but it's pretty intensive work and I'd be fooling myself
if I didn't think I'd missed a couple.

Note that this version should pretty much be able to bootstrap itself
using PostgreSQL now ... but this is untested

mod/survey/graph.php

@@ -402,7 +402,7 @@
 
            if ($aaa) {
                foreach ($aaa as $a) {
-                   if ($a->user == $sid) {
+                   if ($a->userid == $sid) {
                        if ($a->answer1) {
                            $studbuckets1[$i] += $a->answer1;
                            $studcount1[$i]++;
@@ -548,7 +548,7 @@
        if ($aaa) {
            foreach ($aaa as $a) {
                $index = $indexof[$a->question];
-                   if ($a->user == $sid) {
+                   if ($a->userid == $sid) {
                        if ($a->answer1) {
                            $studbuckets1[$index] += $a->answer1;
                            $studcount1[$index]++;