Update configuration and evolutions

Evolutions have been disabled in the configuration file, since they are giving
me some problems, and the database table definitions are quite stable at this
point. The problem is in the table generation by Slick, that is just not quite
right at the moment, will solve it in the future if using evolutions becomes
necessary, but at this point it is simpler to just write by hand the SQL
scripts (which are added here, replacing the one generated by Slick).

Also moduralized a bit more the configuration files, placing the logging
settings into its own file, and updated some settings in the database files.
Remove Virtuslab Unicorn dependency

Virtuslab's Unicorn library is giving me some small headaches, so it is removed
and will implement a by-hand Identifier class that simulates what Unicorn
offers. Also, because of this library dropping, Slick and hence Play-Slick can
be upgraded to latests versions (that were not compatible with Unicorn).

Upgraded ScalaTest too to latest version just published (2.1.0) and ScalaMock
support for it.
Create Identifier trait and use FreeSpec in tests

Since Unicorn's library has been removed, an Identifier trait that does a bit
of what Unicorn did has been created to replace it without much problems. Also
added a IdentifierCompanion to it, the way that Unicorn did. All models have
been updated to use this one Identifier trait instead of the Ids from Unicorn.

All _.Predef objects inside object companions have been removed, making all the
implicits inside them available at the companion level, and added some implicit
definitions more for Play's path binders. Some of the Slick's column mappings
(implicits) have been replaced with the trait MappedTo of Slick 2.0, that now
can be used because of the library upgrade in previous commit.

FlatSpec in BaseSpec has been replaced with FreeSpec, since it imposes no
restrictions in how tests have to be structured, allowing to use simpler and
cleaner specification structures (e.g.: not using anymore that ugly "it").
Use cake pattern in database components

Database components (tables) have been updated to correctly use Slick in its
2.0 version, and implemented a Cake Pattern design, that allows the use of
different database drivers seamlessly: a DAL object is created with the correct
driver (JdbcProfile), and all database components (with its tables) are mixed
in to make use of that specific driver.

Also, mappers have been moved from Model objects to a Mappers trait that lives
only in the database package, achieving a more clean design this way, with less
implicit definitions in the model companion objects.