Allow to open Realm files without correct file suffix

[TimOliver]

From @puttin on April 16, 2015 2:57

as the title

Copied from original issue: realm/realm-cocoa#1762

[TimOliver]

From @jpsim on April 17, 2015 1:17

That's very true. Until we add a way to open realm files without a .realm extension, you can always just rename it to include .realm, make a copy whose name includes .realm or make a symlink with a .realm extension.