Add better errors to the use in alphabetical order sniff.

I find the current version of this sniff to be incredibly opaque as it
is really hard to figure out what the desired order is. Adding the
expected values makes it a bit easier to sort that out.
Fix incorrect line numbers.

Having the right line numbers in errors really helps.
Merge pull request #92 from cakephp/better-errors

Better errors for use statement sniffs