Merge pull request bitcoin#891 from aerosol/replace-elixir-bip39-implementation

Replace elixir bip39 implementation

Author: luke-jr

bip-0039.mediawiki

@@ -138,7 +138,7 @@ Go:
 * https://github.com/tyler-smith/go-bip39
 
 Elixir:
-* https://github.com/izelnakri/mnemonic
+* https://github.com/aerosol/mnemo
 
 Objective-C:
 * https://github.com/nybex/NYMnemonic