Added a dummy builder when using @builder.
Local attribute reifications can be generated.

Now, it's feasible to generate the attribute reifications given a
trait. However we can't refer parent's attributes yet. This won't be
straightforward because there's no tree available for them.
Added attribute reifications.

This has been difficult, because I had to deal with some problems
while finding the parent attributes information. Besides, it has been
difficult as well deciding which is the best design in order to reuse
the legacy code (and it's not clear yet).
Added `apply` method.

Now, @builder generates an apply method which generates instances of
the involved trait.
FIXED: runtime reflection capabilities were broken.

They were extracting the symbol information from the wrong type. It
has been solved and it is working ok.
FIXED: inherited attributes should reuse parent's reifications.
FIXED: reference to parent reifications.

It seems compiler doesn't like too much to use the parent tree to
extract the reifications. I have changed it with a `newTermName`
instead. It's ugly, but it works (although I am pretty sure I will
have bad news caused by these lines in the future).
Radical change to fully reuse the MacroMetamodel.

Working with both trees and types all together was being really hard
so I have changed to a new way of doing the generation. Everything is
noted on #761.
Added attribute reification wrappers.
Added an implementation for the `attributes` value.
Added a @builder test file.
Added the weak alias where we will generate the weakBuilder.
Added support to generate weak builders.
Added apply method (partially).

I have just added both apply(args) and apply() methods. However,
default arguments are not being generated yet (I think this is due to
quasiquote limitations). Besides they are not working fine, because
they have a dependency with `updated`, which is still unimplemented.
Added `get`, `updated` and `modifiables`.

So, we are pretty advanced in order to fully apply macro @builder.
Evidence generation is almost working.
And now, it is fully working.

I forgot to add the `evidence` generation for the default apply method.
Added support for default types.
Almost all tests are passing.

It seems that the `finder` is broken. It's natural if we take into
account that we don't have to search for values as builders. Instead,
we have to dig into the generated companions to find them.

Anyway, the rest of things are working nice. This is really cool!
Finder has been fixed.

Since we changed the way to deploy builders, the way to find them
broke down. After mending it, we can generate the whole model again.