*Untested sql_commands/sql_script support in mysql/postgres/sqlserver

[ssweber]

self.con.executescript is sqlite only.

So I did basic conversion over to how it should be, but not sure how it works if sql_script/commands have things like SELECTS.

Perhaps we consider taking this functionality completely out for mysql/postgres/sqlserver, and point users in the direction of something like: http://execsql.osdn.io/ if they need to execute a script.

[ssweber]

if you end up merging this before I port orders to test properly, I think that'll be OK.

[ssweber]

I tested these and they seem to work OK

[ssweber]

Once again, I'm finding it easier to just have a WIP, but the commits are cleaner this time