[Swift-devel] new variable closing code

[Mihael Hategan]

I committed code to deal with a lot of the nasty little problems related
to array closing.

The compiler now keeps better track of what variables are written and
read and where. It produces more detailed compilation errors, with
pointers to the swift source.

Closing can now happen in the scope that last writes to an array rather
than in the declaration scope. Each handle now has a write reference
count instead of the previous close ids. The reference count is set
initially when a variable is created, decreased when a partial close
occurs, and increased when an iteration that writes to that variable
stars.

Long story short, good stuff!

language/working/q7.swift fails. I think it should.

Now for some turkey. What do you mean all stores are closed? Hmm...