Please use submodules instead of added external binaries

Dear @bitbeans,

To improve the source code can you use git submodules instead of to external binaries?
- https://github.com/DNSCrypt/dnscrypt-proxy

git submodules:
- https://git-scm.com/book/en/v2/Git-Tools-Submodules

Thanks in advance.

Linked to:
- https://github.com/Dola-Shuvi/SimpleDnsCrypt/issues/4

cc: @Dola-Shuvi.