Add flag definitions to questionnaire json
Closes #102

LGTM given by: @jornvandebeek

Squashed commit of the following:

commit 766ce8fd953c3f848a45c88db13cf5790d119fee
Author: Marten Veldthuis <marten@veldthuis.com>
Date:   Tue Oct 14 15:26:23 2014 +0200

    No need to pass along parameters, these are now ivars

commit e0e312bf5e9a4825548c169887249ba845ae92d0
Author: Marten Veldthuis <marten@veldthuis.com>
Date:   Tue Oct 14 15:25:35 2014 +0200

    Give methods better names

commit 983cae78fc248e7818396032b5efba7cf79bc73a
Author: Marten Veldthuis <marten@veldthuis.com>
Date:   Tue Oct 14 15:23:09 2014 +0200

    Defaults can now be given for textvars

commit 88b26acb9bb0408d6b1b797f890e3b1f371d7df4
Author: Marten Veldthuis <marten@veldthuis.com>
Date:   Tue Oct 14 15:21:05 2014 +0200

    Extract BuildAnswer service

commit 9bf2e7d7d8f492988e15607909ea254f6f3b5ca9
Author: Marten Veldthuis <marten@veldthuis.com>
Date:   Tue Oct 14 14:39:07 2014 +0200

    Copy default textvars when creating new answer

commit ed5539c68cdb6d61d0b13dc3447a15435fdec98d
Author: Marten Veldthuis <marten@veldthuis.com>
Date:   Tue Oct 14 14:15:58 2014 +0200

    Autoprefix textvars

commit 9a7b5cfa1cc7dbe4b4efd4634c560bae057c2dd7
Author: Marten Veldthuis <marten@veldthuis.com>
Date:   Tue Oct 14 13:34:25 2014 +0200

    Require that textvars refer to defined textvars

commit 06497e051771ecd0b27c3313f40939f602e4c329
Author: Marten Veldthuis <marten@veldthuis.com>
Date:   Tue Oct 14 11:08:56 2014 +0200

    Clean up initialization of textvars

commit 32583adc849b289757520b28648cfda1bc3a1ca3
Author: Marten Veldthuis <marten@veldthuis.com>
Date:   Mon Oct 13 18:57:13 2014 +0200

    Convert textvars to react

commit bf348b981fe41d6097428d56e6fea4a00225a4ca
Author: Marten Veldthuis <marten@veldthuis.com>
Date:   Mon Oct 13 17:28:13 2014 +0200

    Fix line length

commit 6bde3c9b32574276ff3fe2461ddc24e8b3f2c546
Author: Marten Veldthuis <marten@veldthuis.com>
Date:   Mon Oct 13 16:37:53 2014 +0200

    Walking skeleton
Bump version
Fix rspec 2.x syntax
Update changelog
Fix receive_messages (TODO: update rspec)
Expose textvars definitions in questionnaire json
Fix issue with unsorted textvar keys
Allow creating answers with empty textvars for questionnaires with textvars with no default
Don't count hidden answers as filled in for question groups
Add integration spec testing for not counting hidden questions as answered
Spurious newline
update libv8
add DSL for context free title
added validations
added skip_title to question parameters
remove cft on table builder; add specs to ensure it does not fail
fixed spec typo
added fallback in quby