Make SafeOpenFileAsync less safe

Getting to the bottom of #21

https://github.com/shiftkey/Akavache/commit/b998d9dde9d2d1bce35631db99a8972e48a9542d - tweaking gitignore because noisy
https://github.com/shiftkey/Akavache/commit/9fd224a1980038d78b0907997cac4351c1322d22 - drop if you don't want the tests
https://github.com/shiftkey/Akavache/commit/8c28631de2a90c31e8046331267a5ff5517d01b8 - yes i know its called "Safe" but I really think it shouldn't be creating a file