Use binary dependencies was: Truffle dependency moved to git

[Jaroslav Tulach]

### Thursday 21 of January 2016, 15:44:30 @ Gilles Duboscq ###
> We have binary dependencies for this use-case. Maybe we should start using
> them (set MX_BINARY_SUITES=truffle). Gilles

We should start using binary dependencies by default.

This whole discussion is a proof that people don't want to clone all our 
repositories by default. They are in almost all cases interested only in the 
one code in one repository.

Please, be kind to people trying graal & co. and switch the mx to use binary 
dependencies by default.
-jt