"if not exists" misplaced in create index

[paolino]

I've updated to 0.4.0.0, create index doesn't work anymore at least with sqlite backend.

From sqlite create index docs the if not exists part should be placed before the on part but it's placed after, so I get syntax errors on create index statement.

Same goes for postgresql create index docs, but this I didn't test.

relevant code

commit

[valderman]

Fixed as of 4a536a5391e914cf95bdb83a87a208cc21ff1f05.