Start adding new structure for concurrency

This starts adding what I think is the required structure for decoupling
reporting from running and running concurrently. It adds a `core`,
delegation module and an `interfaces.bdd` base interface (to be
implemented). It also starts drafting the reporter module (which may or
may not be factored into several different modules in the future) and
tweaks our tests' data modeling.
Add a BDD interface example

This adds a simple example, which shall be used for testing the new
revision of the library. It also adds a configuration to compile the
files in `examples/`
Remove unnecessary std.functional import

Not only this is useless, but I think `std.functional.partial` is
deprecated, so it breaks compilation.
Add a spawnable implementation of a reporter

It's a really simple text-only reporter, but it's what's currently
working on the multi-threaded architecture.
Add the BDD interface

Because test suite logic is now at `core`, this is nothing fancy,
really. That's something that makes me pretty happy :) It should be
trivial to add different interfaces.
Add initial working version of core

This adds the first working version of a multi-threaded `bed.core`.
There are still a bunch of things that need fixing and rethinking, but
I'm happy it works.
Tweak the .gitignore and add a `package` module

The `package` module is just for really exporting everything from bed to
the outside world.
Improve on the BDD example, to show concurrency

As it's visible now from the BDD example tests, "bed" is finally fully
concurrent.

(that doesn't mean it's efficient - in face, it's probably slower now -,
but it means we got where we wanted to be from the start)
Make messy improvements to the only reporter

This makes a tweaks and small changes to the only currently implemented
reporter. This will probably become the TextReporter at some point.
Please note I also find this code disgusting. I'm only writing it like
this because I need to iterate faster.
Add a .travis.yml file

This should set-up travis-ci to run our tests on this development
branch.