Squashed commit of the concept feature:

commit e2af951827516755be0bae988627685984052594
Author: Nestor Arocha <nesaro@gmail.com>
Date:   Sun Aug 25 22:20:31 2013 +0100

    moved input and output grammar instanciation to factory

commit 1023e4cf2267d965b2e102ceb5cc04f108f3d437
Merge: 1e01e09 e4bf211
Author: Nestor Arocha <nesaro@gmail.com>
Date:   Sun Aug 25 22:10:45 2013 +0100

    Merge branch 'master' into concept

commit 1e01e0988c1ec9527757881514ab40d2a17971eb
Author: Nestor Arocha <nesaro@gmail.com>
Date:   Sun Aug 25 17:05:28 2013 +0100

    added ConceptTranslator

commit 0245e7f69dccc9c03e5e1aee22f5cd5024938b78
Author: Nestor Arocha <nesaro@gmail.com>
Date:   Sun Aug 25 16:45:33 2013 +0100

    moved Translators to their own Module

commit c5fd5c613cce0bf6c070af32bdd24e194c5253ce
Merge: 3278f71 719127a
Author: Nestor Arocha <nesaro@gmail.com>
Date:   Sun Aug 25 16:27:53 2013 +0100

    Merge branch 'master' into concept

commit 3278f71417721e763485821a64975d6f104ab453
Author: Nestor Arocha <nesaro@gmail.com>
Date:   Sun Aug 25 16:25:07 2013 +0100

    renamed EncodingLexer -> Encoding Translator

commit cf05fecca2b35ffccf92e94baa3905a8186879ff
Merge: 86e3952 6e3a709
Author: Nestor Arocha <nesaro@gmail.com>
Date:   Sun Aug 25 16:17:54 2013 +0100

    Merge branch 'master' into concept

commit 86e39520dca9f27769241a01f2c1d9e63a802504
Author: Nestor Arocha <nesaro@gmail.com>
Date:   Sun Aug 25 08:33:01 2013 +0100

    added conceptalphabet

commit 35b62e4756478fb4560f64067b6bf32484d683f2
Author: Nestor Arocha <nesaro@gmail.com>
Date:   Sun Aug 25 08:27:12 2013 +0100

    added TypeChecking for AlphabetListDefinition

commit efe97ef08440b64493f349c5d9ce41c10ffbeb14
Author: Nestor Arocha <nesaro@gmail.com>
Date:   Sun Aug 25 08:20:40 2013 +0100

    refactored grammar_list -> to_list