* Change test_throws to only check for a single exception type

This way our tests don't mask other exceptions during the testing process.  Inspired by https://github.com/JuliaLang/julia/commit/bda1798a0587ad3b035d4534137d3ce9ed93e5e8

* Update everything in test/ to honor this change (Note, package authors wil still probably need to alter their own package tests)

* I even found a few tests that really wanted to be @test_throws tests but just didn't know it yet.

* Update a mistyped issue number

I'm ambivalent as to whether this makes it into 0.2; it seems more like a hygiene/test thing than anything critical.  The only reason I think it might be beneficial to have merged in sooner than later is for package authors using `@test_throws` in their own code.