adds AlaSQL support

[randomnerd]

http://alasql.org/

[elhigu]

I would like to see lots of tests for this. How does ala sql syntax compare to mysql / postgres / sqlite?

[rhys-vdw]

Hey, I'm for adding more dialects, but I can't really work out anything about AlaSQL's syntax from their website. The interactive console thingy doesn't seem to do anything when I press the 'run query' button.

The documentation suggests that the update statement doesn't support returning, but the client inherits from Postgres. Not sure if this PR addresses this, but obviously the entire thing needs tests.

@randomnerd are you planning to put in the necessary work to get this thing merged? That would mean comprehensive tests and any necessary documentation updates.

[elhigu]

Moved this to issues and added link here if someone likes to finish this.