Update tools.mk to version 0.5
Ignore one dialyzer error

I have not been able to solve this dialyzer error, so its going in the
new ignore file. I have not seen the error appear on a hipe-compiled
Erlang, but I'm not quite sure why that might be the case. I didn't
think hipe-compiled Erlang would differ in the Dialyzer code used.
Make xref analysis pass

* Remove duplicate make target
* Use xref query syntax instead of an ignore file

There is still one warnings about dtrace, this is fixed in the next
commit.
Remove non-existing function call

We're only compiling with R15+ now.
Fix dialyzer warning handling

The dialyzer warning file can't have a blank line, or this will match
_all_ warnings. tools.mk has been updated to check for this, and I've
removed the offending line from the Riak CS dialyzer ignore file.
Remove unused dialyzer replication ignore file

This was used if you did not have the closed-source replication modules
installed, but tools.mk does not yet (if ever?) have support for this.
Update type-spec

ordsets:ordset/0 doesn't exist.