[development] Microsoft SQL Support added

[Moshe Weitzman]

> Unfortunately, it is indeed a hack. You change several sql queries. This 
> will affect either the results and/or the performance.

there is a lot more great code than hack in that patch.

> 
>> I know, that MS-SQL was supported in earlier versions and that you 
>> decided to drop it.
> 
> We dropped it because we lacked a maintainer.

right. i was the old maintainer but didn't have time nor need for ongoing 
maintainence - perhaps you will volunteer to become the new maintainer.

> 
> If you can work more on it and preferably avoid changing any queries in 
> core I suggest that you create a contrib project for this. We can then 
> evaluate the popularity of this and then include it in the release after 
>  that.

i suspect that it will be hard to do this without changing queries. even in 
my version there were problems with the same 2 queries. it is OK to change 
queries as long the meaning is unchanged. ideally, we change to a more 
standards compliant query which is equally performing. it is OK to create 
new DB functions like db_query_range(). if thats not possible, we should 
switch on $db_type and issue differing queries for each.

ideally, you would also support 5.0. In addition to a few schema changes, 
there needs to be a small install.mssql.inc

i agree that this makes sense as a contrib project for now.